If 2cosα=x+(1/x) and 2cosβ=y+(1/y), show that xmyn+1xmyn=2cos(mα+nβ)

If 2cosα=x+(1/x) and 2cosβ=y+(1/y), show that $x^{m} y^{n} + \frac{1}{x^{m} y^{n}}$ =2cos(mα+nβ)

Mixed-up sentence exercise

Put the parts in order to form a sentence. When you think your answer is correct, click on "Check" to check your answer. If you get stuck, click on "Hint" to find out the next correct part.