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Please help me with this question

Please help me with this question-example-1
User Dado
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1 Answer

4 votes

Answer:

cos(x-30)=1/2

Explanation:

We use the following relationship to obtain cos(x)


sin^(2)(x) +cos^(2)(x) +1

From that, we have that cos(x)= sqrt(1-1/4)=sqrt(3) / 4

To obtain the value of cos(x-30), lets remember the following expression:


cos(a-b)=cos(a)*cos(b)+sin(a)*sin(b)

Therefor, we can use that to obtain our desired function cos(x-30)

cos(x)*cos(30)+sin(x)*sin(30)


(√(3) )/(2) * (√(3) )/(2)  +(-1)/(2)*(1)/(2)

=2/4=1/2

User Shanky Singh
by
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