Question

Prove that sin²20º + sin²40º + sin²80º = 3/2

Answer 1

Step-by-step explanation:

sin 20 =0.3420201

sin 40=0.64278761

sin 80=0.98480775

sin 20^2+sin40^2+sin80^2

put those value and square

(0.34)^2+(0.64)^2+(0.98)^2

0.1156+0.4096+0.9604=1.48=1.5

3/2=1.5

hence proved