Sum and Difference Formula Questions Part 1 Part 2 Part 3 Pl

Sum and Difference Formula Questions

Part 1:

Part 2:

Part 3:

Please explain! Thank you!

(1 point) Use an identity to find the exact value of each expression: Note: You are not allowed to use decimals in your answer. sin(58\" ) cos(TF) cos(58\" ) sin( 770)= sin(673°) cos(313°) _ cos(678) sin(313°)= COS

Solution

sin58cos77 +cos58sin77

sin673cos313 - cos673sin313

As per formula sin(A+/- B) =sinAcosB + /-sinBcosA

So, sin58cos77 +cos58sin77 = sin(58+77) =sin135 = sin(90+45) = cos45 = 1/sqrt2

sin673cos313 - cos673sin313 = sin( 673 -313) = sin360 =0