Question

Sin square 45 degree + sin square 45 degree + sin square 10 degree + sin square 18 degree equal to 2 prove that

Answer 1

Step-by-step explanation:

sin25+sin210+sin215+......+sin290

= sin2(90-85)+sin2(90-80)+......+sin285+ sin290

= cos285+cos280+......+sin285+ sin290

= (sin285+cos285)+(sin280+cos280) +......(sin250+cos250)+sin245+ sin290

= 1+1+...8 times + 1/2 + 1

=9.5 Ans