Math, asked by rakesh261, 1 year ago

sinπ/10+sin13π/10=-1/2

Answers

Answered by gagan280799
2
sinπ/10×sin13π/10 =-sinπ/10×sin3π/10 =-sinπ/10×Cos2π/10 =-sinπ/10×[1-2(Sinπ/10)^2] =-(V5-1)/4 [1-2[(V5-1)/4]^2] =-(V5-1)/4 * 4(V5+1)/16 =-1/4 Sin 18=sin π/10 = (V5-1)/4
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