A rope of length 14 feet is arranged in the shape of a sector of a circle with central angle theta radians, as shown in the accompanying figure. Write the area of the sector, A, as a function of theta.

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