I'm having trouble with one problem. The question aske me to finf the amount of power from the equation I found for work. Here is the equation for work: W=F*v*t*cos(theta) I am supposed to come up with an equation that will tell me how much power this is using the variables in the equation. A friend told me to take the derivative but I'm nto sure how to. How do i go about this? Oh and this as well: To stretch a spring a distance x_1 from its unstretched length, an amount of work of W must be done. How much work must be done to compress this spring a distance x_2 from its unstretched length?