Problem of the Week

Updated at Sep 5, 2016 4:40 PM

This week's problem comes from the calculus category.

How would you differentiate sec⁡x+x\sec{x}+x?

Let's begin!



ddxsec⁡x+x\frac{d}{dx} \sec{x}+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)).
(ddxsec⁡x)+(ddxx)(\frac{d}{dx} \sec{x})+(\frac{d}{dx} x)

2
Use Trigonometric Differentiation: the derivative of sec⁡x\sec{x} is sec⁡xtan⁡x\sec{x}\tan{x}.
sec⁡xtan⁡x+(ddxx)\sec{x}\tan{x}+(\frac{d}{dx} x)

3
Use Power Rule: ddxxn=nxn−1\frac{d}{dx} {x}^{n}=n{x}^{n-1}.
sec⁡xtan⁡x+1\sec{x}\tan{x}+1

Done
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