248 lines
5.8 KiB
Markdown
248 lines
5.8 KiB
Markdown
title:: Using R as a Calculator
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- #[[ST2001 Labs]]
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- **Previous Topic:** null
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- **Next Topic:** [[Describing Data in R]]
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- No relevant slides
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-
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- ## Basic Algebra in R
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- ### Addition #card
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card-last-interval:: 33.64
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card-repeats:: 4
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card-ease-factor:: 2.9
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card-next-schedule:: 2022-12-18T07:44:00.469Z
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card-last-reviewed:: 2022-11-14T16:44:00.470Z
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card-last-score:: 5
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- ```R
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# to add numbers in R, simply use "+"
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2+2
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```
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- Output:
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- ```R
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[1] 4
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```
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- ### Subtraction #card
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card-last-interval:: 33.64
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card-repeats:: 4
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card-ease-factor:: 2.9
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card-next-schedule:: 2022-12-18T07:44:48.506Z
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card-last-reviewed:: 2022-11-14T16:44:48.506Z
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card-last-score:: 5
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- ```R
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# to subtract numbers in R, simply use "-"
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4-2
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```
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- Output:
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- ```R
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[1] 2
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```
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- ### Multiplication #card
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card-last-interval:: 33.64
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card-repeats:: 4
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card-ease-factor:: 2.9
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card-next-schedule:: 2022-12-18T07:46:18.737Z
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card-last-reviewed:: 2022-11-14T16:46:18.738Z
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card-last-score:: 5
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- ```R
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# to multiply numbers in R, simply use "*"
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5*2
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```
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- Output:
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- ```R
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[1] 10
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```
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- ### Division #card
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card-last-interval:: 33.64
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card-repeats:: 4
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card-ease-factor:: 2.9
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card-next-schedule:: 2022-11-22T23:24:36.469Z
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card-last-reviewed:: 2022-10-20T08:24:36.470Z
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card-last-score:: 5
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- ```R
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# to divide numbers in R, simply use "/"
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10/5
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```
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- Output:
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- ```R
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[1] 2
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```
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- ### Exponents #card
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card-last-interval:: 33.64
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card-repeats:: 4
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card-ease-factor:: 2.9
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card-next-schedule:: 2022-12-18T07:51:39.910Z
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card-last-reviewed:: 2022-11-14T16:51:39.911Z
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card-last-score:: 5
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- ```R
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# use "^" to raise a number to a power
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3^2
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3^{-1} # use curly braces
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```
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- Output:
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- ```R
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[1] 9
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[1] 0.3333333
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```
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- ### Square Roots #card
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card-last-interval:: 33.64
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card-repeats:: 4
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card-ease-factor:: 2.9
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card-next-schedule:: 2022-12-18T07:37:35.704Z
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card-last-reviewed:: 2022-11-14T16:37:35.705Z
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card-last-score:: 5
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- ```R
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# use the function "sqrt()" to get the square root of a number in R
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sqrt(16)
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```
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- Output:
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- ```R
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[1] 4
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```
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-
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- ### Modulus #card
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card-last-interval:: 33.64
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card-repeats:: 4
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card-ease-factor:: 2.9
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card-next-schedule:: 2022-12-18T07:38:53.453Z
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card-last-reviewed:: 2022-11-14T16:38:53.454Z
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card-last-score:: 5
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- ```R
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# use "%%" to get the modulus
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19%%6
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```
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- Output:
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- ```R
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[1] 1
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```
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- ## Rounding in R
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- ### Absolute Value #card
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card-last-interval:: 33.64
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card-repeats:: 4
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card-ease-factor:: 2.9
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card-next-schedule:: 2022-12-18T07:44:02.326Z
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card-last-reviewed:: 2022-11-14T16:44:02.327Z
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card-last-score:: 5
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- ```R
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# use "abs()" to get absolute value in R
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abs(-1)
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```
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- Output:
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- ```R
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[1] 1
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```
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- ### Rounding #card
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card-last-interval:: 29.26
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card-repeats:: 4
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card-ease-factor:: 2.66
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card-next-schedule:: 2022-12-13T22:41:14.492Z
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card-last-reviewed:: 2022-11-14T16:41:14.492Z
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card-last-score:: 5
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- The function `round()` in R goes not necessarily do what you would expect when rounding numbers ending in **.5** - ^^it rounds to the nearest **even** number.^^
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- If you always round up numbers ending in .5, then you are causing an upwards bias.
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- The rounding to even numbers will tend to average out at a zero bias, as 50% go up and 50% go down.
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- ```R
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# use "round()" to round
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round(1.5)
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round(0.5)
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round(0.7)
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```
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- Output:
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- ```R
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[1] 2
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[1] 0
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[1] 1
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```
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- ## $\pi$ in R #card
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card-last-interval:: 33.64
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card-repeats:: 4
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card-ease-factor:: 2.9
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card-next-schedule:: 2022-12-18T07:38:10.483Z
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card-last-reviewed:: 2022-11-14T16:38:10.484Z
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card-last-score:: 5
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- ```R
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# to get pi in R, simply use the in-built constant "pi"
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pi
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```
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- Output:
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- ```R
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[1] 3.141593
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```
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- ## Trigonometric Functions in R
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- ### Sine in R #card
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card-last-interval:: 33.64
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card-repeats:: 4
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card-ease-factor:: 2.9
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card-next-schedule:: 2022-12-15T02:31:07.981Z
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card-last-reviewed:: 2022-11-11T11:31:07.981Z
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card-last-score:: 5
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- ```R
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# to get the sine of a number in R, use the function "sin()"
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sin(0.5 * pi)
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sin(pi)
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```
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- Output:
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- ```R
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[1] 1
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[1] 1.224647e-16
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```
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- ^^**Note:**^^ $1.224606e-16 \approx 0$. Due to the way computers store numbers, decimals are often slightly off, so $sine(\pi) \ne 0$ even though it should, of course, be equal to zero. Be careful of this!
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- ### Cosine in R #card
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card-last-interval:: 33.64
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card-repeats:: 4
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card-ease-factor:: 2.9
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card-next-schedule:: 2022-12-18T07:45:11.108Z
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card-last-reviewed:: 2022-11-14T16:45:11.109Z
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card-last-score:: 5
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- ```R
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# use "cos()" to get cosine
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cos(0)
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```
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- Output:
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- ```R
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[1] 1
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```
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- ### Tangent in R #card
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card-last-interval:: 33.64
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card-repeats:: 4
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card-ease-factor:: 2.9
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card-next-schedule:: 2022-12-18T07:51:39.012Z
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card-last-reviewed:: 2022-11-14T16:51:39.012Z
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card-last-score:: 5
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- ```R
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# use "tan()" to get tangent
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tan(0)
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```
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- Output:
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- ```R
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[1] 0
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```
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- ## Logarithms in R
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- ### Natural Log #card
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card-last-interval:: 28.3
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card-repeats:: 4
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card-ease-factor:: 2.66
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card-next-schedule:: 2022-12-07T19:44:02.657Z
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card-last-reviewed:: 2022-11-09T12:44:02.657Z
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card-last-score:: 3
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- ```R
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log(1)
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```
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- Output:
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- ```R`
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[1] 0
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```
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- ### Logs to a Given Base #card
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card-last-interval:: 4
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card-repeats:: 2
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card-ease-factor:: 2.66
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card-next-schedule:: 2022-11-22T18:34:16.626Z
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card-last-reviewed:: 2022-11-18T18:34:16.626Z
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card-last-score:: 5
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- ```R
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# log<base>()
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log10(100)
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```
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- Output:
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- ```R
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[1] 2
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``` |