Here's the question you clicked on:
burhan101
What is the first value of of t greater than zero for which the derivative is greater than zero?
\[\huge f'(x)\frac{ sintcost }{ 25 \pi }\]
Uh... there's no "first" value.
that's what my question states :S
Are they asking to solve for t, equation the derivative to zero?
At t=0, the derivative will be 0. For 0<t<\(\frac{\Large\pi}{2}\) the derivative will be positive because sin and cos will both be positive.
\[T = 0 + \left| \delta t \right|\]