What is this answer plz help

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.

Which sum or difference identity would you use to verify that cos (180° - q) = -cos q? a.) sin (a -b) = sin a cos b – cos a sin b b.) cos (a -b) = cos a cos b – sin a sin b c.) cos (a -b) = cos a cosb + sin a sin b d.) sin (a + b) = sin a cos b + cos a sin b

Awindow has the shape of a rectangle with a semi circle at the top. find the approximate area of the window using the dimensions shown. 4ft by 8ft