# calculus

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the height in feet of a rocket from ground level is given by the function f(t)= -16t^2+160t. what is the instantaneous velocity of the rocket 3 seconds after it is launched?

A 32 feet/sec
B 64 feet/sec
C 12 feet/sec
D 10 feet/sec
E 8 feet/sec

• calculus -

okay - another power example. What do you get?

• calculus -

do i plug 3 in for t?

• calculus -

first take the derivative, which is the velocity at any instant.

ds/dt = ft/s, or velocity

Plug 3 into that.

• calculus -

its going to be 32 hun

• calculus -

Hmm. How did you get that, jessica?

f'(t) = -32t + 160
f'(3) = -96 + 160 = 64

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