Lecture 2

Question 1

Logical Operators

Answer 1

< less than
> greater than
<= less than or equal to
>= greater than or equal to
== exactly equal to
!= not equal to
!x not x
x|y x or y
x&y x and y
isTRUE(x) test if x is TRUE

isTRUE() returns TRUE if its argument value is equivalent to TRUE, and returns FALSE otherwise. isTRUE() makes R programming much easier.

Question 2

abs(…)

Answer 2

Used to get absolute values.

Question 3

sqrt(…)

Answer 3

Square root.

Question 4

exp(…)

Answer 4

Used to calculate the power of e.
The exponential constant is an important mathematical constant and is given the symbol e. Its value is approximately 2.718.

Question 5

log(…)

Answer 5

Natural log.

Question 6

log(v,b)

Answer 6

v - value for which you must take log
b - specified base

Question 7

round(v,s)

Answer 7

Round v to s digits.

Question 8

factorial(n)

Answer 8

Factorial of a whole number ‘n’ is defined as the product of that number with every whole number less than or equal to ‘n’ till 1. For example, the factorial of 4 is 4 × 3 × 2 × 1, which is equal to 24.