(2cos (11pi/5)+8 sin(13pi/10)) / cos pi/5

Question

(2cos (11pi/5)+8 sin(13pi/10)) / cos pi/5

Answer 1

(2cos (11pi/5)+8 sin(13pi/10)) / cos pi/5 = (2cos (2pi +pi/5)+8 sin(3pi/2-2pi/10)) / cos pi/5 =(2cos (pi/5)-8 cos(pi/5)) / cos pi/5=(-6cos (pi/5)) / cos pi/5=-6