posted by kriti .
a particle moves along the y axis so that its position at any time t, for 0 is less than or equal to t which is less than or equal to 5, is given by y(t)=t^4-18t^2. in which intervals is the particle speeding up?
so when t=less than sqrt3, y"=+ *- or negagive, slowing down.
t= greater than sqrt3, y"=+ * + speeding up.