Skip to content
  • Open the math solver
  • Ask the AI tutor
  • Find an AP course
  • Create a quiz
  • Open the calculator
  • Graphing Calculator
  • Browse all calculators
  • Read math guides
↑ ↓Enter to open · Esc to close
Solve a problem
DerivativesCalculusCollegeabout 0:51

Differentiate cos(x^2): animated lesson

A narrated, step-by-step derivatives video lesson with captions. Final answer: f'(x) = -(2sin(x²)·x).

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 (0.3 MB) · Captions (WebVTT)

Steps on screen

  1. 1. The problem
    Finding a derivative
    ddx[cos⁡(x2)]\frac{d}{dx}\left[\cos\left({x}^{2}\right)\right]
  2. 2. Step by step
    1. ddx[cos⁡(x2)]=−(2sin⁡(x2)x)\frac{d}{dx}\left[\cos\left({x}^{2}\right)\right] = -\left(2\sin\left({x}^{2}\right) x\right)
      Chain rule — d/dx[cos u] = −sin u · u′
    2. ddx[x2]=2x\frac{d}{dx}\left[{x}^{2}\right] = 2x
      Power rule: d/dx[xⁿ] = n·xⁿ⁻¹
    3. f′(x)=−(2sin⁡(x2)x)f'(x) = -\left(2\sin\left({x}^{2}\right) x\right)
      Combine and simplify
  3. 3. The answer
    f′(x)=−(2sin⁡(x2)x)f'(x) = -\left(2\sin\left({x}^{2}\right) x\right)

    f'(x) = -(2sin(x²)·x)

  4. 4. Check
    • Cross-checked numerically against an independent symbolic differentiator at 8 sample points ✓

Transcript

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

Step by step. Chain rule — d by d x[cos u] equals negative sin u times u prime. Power rule: d by d x[x to the power n] equals n times x to the power n minus 1. Combine and simplify.

The answer. So the answer is f prime of x equals -(2sin(x squared) times 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.

Differentiate cos(x^2): Derivatives Step-by-Step Lesson