trig/cal
posted by Anonymous .
how does pih^3/12 simplify to pih^2/4?
If you divide denominator by 3 you get 4 and then I guess the 3 goes away leaving a 2? But if this is correct why does this work?

Did you do the antiderivative?
INT PI*H^2/4 dh = PI H^3/12
and likewise,
d/dh (PI H^3/12)= PI H^2/4 
no i took the derivative. i see now
d/dh (PI*h^3/12) = 3PI*h^2/12 = PI*h^2/4
sorry i guess this was the wrong forum