Question

A body is moving according to the equation x=a+bt2-ct3.Then its instantaneous speed is given by:-

Answer 1

same
v is equal to 2bt + 3ct2

speed is 2bt + 3ct2

Answer 2

x = a + bt^2 - ct^3
Differentiate with dt
x/dt = (a + bt^2 - ct^3)/dt
v = 2bt - 3ct^2

It’s instantaneous speed is 2bt - 3ct^2