SOLVED:The natural logarithm function, ln, is defined so that e^lnx=x for any positive number x (a) Sketch a graph of the natural logarithm function. (b) Prove the identities lna b=lna lnb and lna^b=b lna (c) Prove that (d)/(d x) lnx=(1)/(x) (d) Derive the useful approximation ln(1 x) ≈x, which is valid when |x| ≪1 . Use a calculator to check the accuracy of this approximation for x=0.1 and x=0.01.