parametric equation and maxmium/minimum problem
could u help me with these?
James blowing machine blows spherical bubbles whose surface area ,S, increases at the rate of 25cm^2/s. What is the rate the of increase of the radius,r, when the radius is 5cm?
I ended up with 0.199cm/s
find maximum,minimum or point of inflection
give the values of x which are concave down
i got (-1,4) as maximum and (1,0) as minimum unsure about concave bit =S
is this correct?
thanks in advance