SOLUTION: Hello Tutor, I really need your help to answer this question please. 3. Verify the following identity by using an angle sum identity: cos (2x) = 1 � 2(sin2 x). Hint (2x = x +

Question 971855: Hello Tutor, I really need your help to answer this question please.
3. Verify the following identity by using an angle sum identity: cos (2x) = 1 � 2(sin2 x). Hint (2x = x + x)
Found 2 solutions by Boreal, anand429:
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
double angle identity for cos (x+y)
=cosx*cosy - sinx*siny
=cosx^2 - sinx^2 since y=x
But cos^2 x + sin^2 x =1
Therefore, cos (2x)= 1-sin^2 x -sin^2 x substituting in two lines above.
cos (2x)=1-2 sin^2 x
Answer by anand429(138) (Show Source): You can put this solution on YOUR website!
cos(2x) = cos(x+x)
=cosx*cosx -sinx*sinx
=
=
=
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