Question

Given sinx=0.9 , what is cosx ? Enter your answer as a decimal in the box. Round only your final answer to the nearest hundredth.

Answer 1

The answer is 0.44. I don't know how it got there but that was the answer that the quiz said was correct lol

Answer 2

It is given sinx=0.9 .We need to find cosx.

We use the identity :

$sin^{2} x + cos^{2} x =1$

Substituting sinx=0.9

$(0.9)^{2} +cos^{2} x =1$

$0.81+cos^{2} x=1$

Substracting 0.81 both sides:

$cos^{2} x =1-0.81$

$cos^{2} x=0.19$

Taking root of both sides cosx=0.435

Rounding to nearest hundredth

cosx=0.44.