Question

Find the value of sin^2 10 + sin^2 80​

Answer 1

Answer:

Sin85 = Cos5 .. .. .. .. So Sin^2 5 + Sin^2 85 = 1

Sin80 = cos10.. .. .. .. So Sin^2 10 + Sin^2 80 = 1

and so on till sin50 = cos40 .. .. .. So Sin^2 40 + Sin^2 50 = 1

Sin90 = 1

sin^2 45 = 1/2

Thus the series sums up to 9.5