d/dx (\dfrac{t}{2}x^{3}-(1-t)\cdot x^{2}+6-t) = \frac{3t}{2}x^{2}-2x+2tx

Uh oh! Wolfram|Alpha doesn't run without JavaScript.

Please enable JavaScript. If you don't know how, you can find instructionshere.Once you've done that, refresh this page to start using Wolfram|Alpha.