two problems i have differentiated. need to find stationary point and state if max or min value.
this is where im stuck. do i make dy/dx= 0?
you've erred in your derivative calculation, though it would not matter in calculating the stationary point in this case!
At a stationary point, this is zero, so
This is zero when t=0
You would have gotten the correct answers in spite of your errors! coincidentally