# Calculus- Find the maximum height of a function

A ball is thrown into the air with an initial velocity of $16 ft/s$. its height after $t$ seconds is given by $f(x) = 16t-4t^2$ . After how many seconds does the ball reach its maximum height?

I can't remember back whether this fell under the derivative section or the Limit section, therefore i am stuck

• Are you sure the equation is right? From what I see its max will be at t=0 – Matt Dec 2 '15 at 2:07
• Sorry, I had a - infront of the 16. my bad. – Jon Roy Dec 2 '15 at 2:09
• @Matt - You may be right, however i got two. – Jon Roy Dec 2 '15 at 2:16
• Yeah, the formula changed, in the first version it was just 16, not 16t - that or I missaw. 2 is right, get it by setting the derivative to 0 – Matt Dec 2 '15 at 2:17