Test for pointwise and uniform convergence on the given set. [The Weierstra M-Test might be helpful.] a. (f(x)=sum_{n=1}^{infty} frac{ln n x}{n^{2}}, x in[1,2]). b. (f(x)=sum_{n=1}^{infty}

Test for pointwise and uniform convergence on the given set. [The Weierstraß M-Test might be helpful.]

a. \(f(x)=\sum_{n=1}^{\infty} \frac{\ln n x}{n^{2}}, x \in[1,2]\).

b. \(f(x)=\sum_{n=1}^{\infty} \frac{1}{3^{n}} \cos \frac{x}{2^{n}}\) on \(R\).