# Power series

Hello, can anyone help me on this one? I am finding problem pretty tricky indeed.

I know the power series (or Taylor series) for cosx is

1-x^2/2!+x^4/4!-x^6/6!+... (It is convergent for all element x is a member of set R)

Q) Write down the power series for cos(u^2) up to the u^24 term.