Prove the following: \text { a) }(3+j 4)^{-\frac{1}{2}}+(3-j 4)^{-\frac{1}{2}}=\frac{4}{5} \text { b) } \sqrt{j}+\sqrt{-j}=\sqrt{2} \text { c) }(a+j b)^{\frac{1}{2}}=x+j y \text {, then show that }(a-j b)^{\frac{1}{2}}=x-j y