Question

cos square (90+alpha)+cos square (180_alpha)​

Answer 1

Answer:

$\sin {}^{2} \alpha + \cos {}^{2} \alpha = 1$

So the answer is 1

Hope it helps.

Answer 2

Step-by-step explanation:

cos^2(90+alpha) = sin^2alpha

cos^2(180-alpha)= -cos^2 alpha

cos^2(90+alpha)+cos^2(180-alpha)=sin^2alpha-cos^2alpha

cos(x+y)=cos(x)cos(y)-sin(x)sin(y)

If y=x, then

cos(2x)=cos^2(x)-sin^2(x)

Therefore, it can be clearly seen that

f(x)=-cos(2x)

Therefore,

f(pi/12)=-cos(2pi/12)=-cos(pi/6)

=-under-root(3)/2

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