Question

sin^2 5° + sin^2 10° + sin^2 15° +...+ sin^ 2 90° = 9×1/2​

Answer 1

Answer:

sin^2 5 + sin^2 10 + sin^2 15 + …… + sin^2 75 + sin ^2 80 +sin^2 85 + sin^2 90

(sin^2 5 + sin^2 85 )+( sin^2 10 + sin^2 80) +( sin^2 15 + sin^2 75) + ……..+ sin ^2 45 + sin^2 90

(sin^2 5 + cos^2 5 )+( sin^2 10 + cos^2 10) +( sin^2 15 + cos^2 15) + ……..+ sin ^2 45 + sin^2 90

(1 + 1 + 1 +1 + 1 + 1 +1 + 1 ) + 1/2 +1

19/2