Calculusderivatives
posted by Jake on .
Explain how to do these questions~
1. An object moves in a straight line with its position at time t seconds given by s(t) = 32t+t^2, where s is the measured in metres. At what time is the object not moving?
2. Determine the coordinates of the point(s) on the graph of y=3x 1/x at which the slope of the tangent is 7.

s=32t+t^2
ds/dt=2+2t
when it is not moving, ds/dt =0, solve for t.
y=(3x1)/x= 31/x
dy/dx=+1/x^2
if slope is 7, then
7=1/x^2
x^2=1/7
x= sqrt(1/7)
y=(3x1)/x solve for y. 
For number one we find the derivative of 32t+t^2
wouldn't that be t2? 
Oh crap nvm!

So for number 1 the answer is t=1
2+2t=0
2t=2
2/2=1