If you are required to find exact values (which would be mentioned in the instructions for the exercises), then find sine and cosine for each angle, then use the angle-difference formula for the cosine.If sin(x) = 1/3 and sec(y) = 29/21, where x and y lie between 0 and pi/2, what is cos(x − y)?
Hint: Use the following identities: [imath]\sec \alpha = \frac{1}{\cos \alpha} \quad ; \quad \sin^2 \alpha + \cos^2 \alpha =1 \quad ; \quad \cos(\alpha - \beta)=\cos \alpha\cos\beta+\sin\alpha\sin\beta[/imath]If sin(x) = 1/3 and sec(y) = 29/21, where x and y lie between 0 and pi/2, what is cos(x − y)?