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DerivativesCalculusCollegeabout 0:39

Find d/dx(cos(x)): animated lesson

A narrated, step-by-step derivatives video lesson with captions. Final answer: f'(x) = -sin(x).

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Video with a synthetic English voice and captions. Pick another language for subtitles in that language, or open the interactive version.

Video narrated by a synthetic voice (Piper TTS, en_US-ljspeech-high voice (LJ Speech dataset, public domain)); the steps come from our maths engine and the answer was checked independently. Download MP4 (0.2 MB) · Captions (WebVTT)

Steps on screen

1. The problem
Finding a derivative
$\frac{d}{dx}\left[\cos\left( x\right)\right]$
2. Step by step
1. $\frac{d}{dx}\left[\cos\left( x\right)\right] = -\sin\left( x\right)$
  d/dx[cos x] = −sin x
2. $f'(x) = -\sin\left( x\right)$
  Combine and simplify
3. The answer
$f'(x) = -\sin\left( x\right)$
f'(x) = -sin(x)
4. Check
- Cross-checked numerically against an independent symbolic differentiator at 8 sample points ✓

Transcript

The problem. Here is the problem: d by d x(cos(x)). Find the derivative of (cos(x)) with respect to x.

Step by step. d by d x[cos x] equals negative sin x. Combine and simplify.

The answer. So the answer is f prime of x equals negative sin(x). The derivative is built from the outside in: sums split into terms, constants factor out, products and quotients use their rules, and every composite function multiplies by the derivative of its inside (chain rule).

Check. Cross-checked numerically against an independent symbolic differentiator at 8 sample points, which checks out.

About derivatives

Differentiate with the power, product, quotient and chain rules, including higher derivatives.

Find d/dx(cos(x)): Derivatives Step-by-Step Lesson