Hi. I have to show that(adsbygoogle = window.adsbygoogle || []).push({});

x(t)=c1 cos(wt) + c2 sin(wt) '(1)'

and

x(t) = A sin(wt + phi)

are equivalent. I know I have to use

sin(alpha + beta) = sin(alpha)cos(beta) + cos(alpha)sin(beta)

or

cos(alpha +beta)= cos(alpha)cos(beta) - sin(alpha)sin(beta)

I have been strugling with this problem for a long time, trying to multiply expression (1) with cos(beta) and so on but I don't think I am getting anywere. Could someone please give me a little hint how to begin on this problem?

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# A trigonometric problem

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