If I say that the function f:R->R has two derivatives, with f(0) = f'(0) = 0 and the absolute value of f"(x) is less than or equal to one, if the absolute value of x is less than or equal to 1. How can I prove that:
f(x) <= 1/2 if x <= 1© BrainMass Inc. brainmass.com March 4, 2021, 5:45 pm ad1c9bdddf
|f''(x)| <= 1 for |x| <= 1
=> -1 <= f''(x) <= 1 for -1<=x<=1
integrate from 0 to x:
=> -x <= f'(x) <= x for -1<=x<=1 (because ...
Integration is used to prove a function is true. The absolute value of x being less or equal to one is computed.