Question

(b) sin 20° sin 40° sin 80° sin 90º =​

Answer 1

Answer:

we know that sin 90 =1

Step-by-step explanation:

so the question becomes sin 20 sin 40 sin 80

sin 20 sin (60 --20) sin (60 +20)

(1/4) sin(3(20)) ( since, sin theta sin (60-- theta) sin (60+theta) =(1/4) sin (3(theta))

(1/4)sin 60

(1/4)( root three/2)

so the answer is (root three / 8)