2. Yes, consider it! What is the MacLaurin series of that function? (You don't have to take derivatives, etc. to find that. The MacLaurin series for log(1+ x) is $x- x^2/2+ x^3/3+ \cdot\cdot\cdot= \sum_{n=1}^\infty (-1)^nx^n/n$. Replace that "x" with " $x^2$" and multiply each term by $x^3$.) What should you set x equal to to get the series you want?