Question

What is the exact vaule for `sin((3pi)/4)` and `sin((9pi)/4)`?

Answer 1

`sin(3/4 pi) =(sqrt(2))/2` and `sin(9/4 pi) =(sqrt(2))/2`

Solution:

You solve such problems by using the reduction formulas for trigonometric functions.

1) `sin(3/4 pi)=sin(pi - pi/4) = sin(pi/4) = (sqrt(2))/2`
2) `sin(9/4 pi)=sin(2pi+pi/4)=sin(pi/4) = (sqrt(2))/2`