1)(cos(2^x))' = (2^x)'*(-sin(2^x)) = -ln2*2^x*sin(2^x)
2)(1-x^3)/(sqrt(pi)*x) = 1/sqrt(pi)*(1/x-x^2) => y' = 1/sqrt(pi)*( -1/x^2-2x)
1)(cos(2^x))' = (2^x)'*(-sin(2^x)) = -ln2*2^x*sin(2^x)
2)(1-x^3)/(sqrt(pi)*x) = 1/sqrt(pi)*(1/x-x^2) => y' = 1/sqrt(pi)*( -1/x^2-2x)