show that has a root in the interval (0,1). 3. Prove the following statements using Mean Value Theorem. (a) For every real numbers a and b, we have - - |cos a cos b |a b|. (b) For every a, b (-7), we have (c) For every t> -1, we have - |tan a tan b| |a b|. - In(1+t) t 1+t'