Question

Which of the following is equivalent to cos x?
A) TAN Y
B) TAN X
C) COS Y
D) SIN Y

Answer 1

ANSWER

D) sin Y

EXPLANATION

The given triangle is a right triangle.

This implies that that:

$x + y = 90 \degree$

Then we have

$y= 90 - x$

Recall that

$\cos(x) = \sin(90 - x)$

But

$90 - x = y$

When we do the substitution, we get,

$\cos(x) = \sin(y)$

Therefore cos(x) is a equivalent to sin(y).

The correct answer is D.