Question

Which of the statements below provides evidence that sine and cosine are cofunctions?

sin(30°)=cos(30°)
sin(60°)=-cos(60°)
sin(30°)=cos(-30°)
sin(30°)=cos(60°)

Answer 1

The sine of an angle equals the cosine of its complement.

Answer: D. sin(30°) = cos(60°)

Answer 2

Option D. is the answer.

Explanation:

In this question we have to find the statement that provides incidence that sine and cosine are co-functions.

As we know co function identities clearly say

(
`sin((\pi )/(2)-x)=cosx`

A. For x = 30° or
`(\pi )/(6)`

`sin((\pi )/(2)-(\pi )/(6))=cos((\pi )/(6))`

`sin(\pi )/(3)=cos(\pi )/(6)`

Or
`sin(60)=cos(30)`

B. For x = 60°

sin(90-60) = cos(60)

sin(30) = cos(60)

Which is similar to option D.

Therefore, Option D. is the the correct answer.