Question

Given that sin ø 21/29, what is the value of cos ø, for 0° < ø < 90%

Answer 1

Answer:

$\frac{20}{29}$

Step-by-step explanation:

Let x replace theta.

Apply pythagorean trig identity

$\sin {}^{2} (x) + \cos {}^{2} (x) = 1$

$(\frac{21}{29} ) {}^{2} + \cos {}^{2} (x) = 1$

$\frac{441}{841} + \cos {}^{2} (x) = 1$

$\cos {}^{2} (x) = 1 - \frac{441}{841}$

$\cos {}^{2} (x) = \frac{400}{841}$

$\cos(x) = \frac{20}{29}$

Cosine is positve in 1st quadrant so the answer is

$\frac{20}{29}$