Question

Given the value of cos 50° ? 0.6428, enter the sine of a complementary angle. Use an expression relating trigonometric ratios of complementary angles.

Answer 1

ANSWER

$\sin(40) \degree = 0.6428$

EXPLANATION

The sine and cosine ratios are complementary.

This means that:

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

We were given that,

cos(50°)=0.6428

We want to find the sine of the complement of this angle.

$\cos(50\degree) = \sin(90 -5 0) \degree$

$\cos(50\degree) = \sin(40) \degree$

This implies that,

$\sin(40) \degree = 0.6428$