Question

(c)
cos 70/sin 20 + cos 59°/sin 31°= 8sin square 30​

Answer 1

Answer:

cos 70/sin 20 + cos 59°/sin 31°= 8sin² 30

LHS= cos 70/sin 20 + cos 59°/sin 31°

= cos70/sin(90-70). + cos59/sin(90-59)

= cos70/cos70 + cos 59 /cos59

= 1+1= 2

RHS = 8sin²30= 8× 1/4 = 2

LHS=RHS

hence proved