Question

Select the correct answer.

What is the domain of y= cos (x)

a.2pie
b. [-1,1]
c. (-infinity, infinity)
d. [0,infinity)

Answer 1

The answer should be C.

The range of definition of the cosine function is all real numbers.
`R`

It is also periodic in
`2\pi`.

It is an even function.
`f(x)=f(-x)`

It can also be written in this form.

• 
  `cos(x)=(e^(-ix)+e^(ix))/(2)`