Problem of the Week

Updated at Apr 4, 2016 3:25 PM

This week's problem comes from the calculus category.

How would you differentiate x7sinx{x}^{7}-\sin{x}?

Let's begin!



ddxx7sinx\frac{d}{dx} {x}^{7}-\sin{x}

1
Use Sum Rule: ddxf(x)+g(x)=(ddxf(x))+(ddxg(x))\frac{d}{dx} f(x)+g(x)=(\frac{d}{dx} f(x))+(\frac{d}{dx} g(x)).
(ddxx7)(ddxsinx)(\frac{d}{dx} {x}^{7})-(\frac{d}{dx} \sin{x})

2
Use Power Rule: ddxxn=nxn1\frac{d}{dx} {x}^{n}=n{x}^{n-1}.
7x6(ddxsinx)7{x}^{6}-(\frac{d}{dx} \sin{x})

3
Use Trigonometric Differentiation: the derivative of sinx\sin{x} is cosx\cos{x}.
7x6cosx7{x}^{6}-\cos{x}

Done