Prove that f (x) = ax + b, where a and b are constants and a > 0 is an strictly increasing function for all real values of x. without using the derivative.
Prove that the function f (x) = sinx is
(i) strictly increasing in
(ii) strictly decreasing in
(iii) neither increasing nor decreasing in .
Prove that the function f (x) = cos x is
(i) strictly increasing in
(ii) strictly decreasing in
(iii) neither increasing nor decreasing in