Problem of the Week

Updated at Dec 29, 2014 2:41 PM

For this week we've brought you this calculus problem.

How can we solve for the derivative of \(3x-\cos{x}\)?

Here are the steps:



\[\frac{d}{dx} 3x-\cos{x}\]

1
Use Sum Rule: \(\frac{d}{dx} f(x)+g(x)=(\frac{d}{dx} f(x))+(\frac{d}{dx} g(x))\).
\[(\frac{d}{dx} 3x)-(\frac{d}{dx} \cos{x})\]

2
Use Power Rule: \(\frac{d}{dx} {x}^{n}=n{x}^{n-1}\).
\[3-(\frac{d}{dx} \cos{x})\]

3
Use Trigonometric Differentiation: the derivative of \(\cos{x}\) is \(-\sin{x}\).
\[3+\sin{x}\]

Done
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