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Derivative of sin⁡(−x)\sin\left(-x\right)

The derivative of sin⁡(−x)\sin\left(-x\right) is −cos⁡(−x)-\cos\left(-x\right).

f(x) =
ddx[sin⁡(−x)]=−cos⁡(−x)\frac{d}{dx}\left[\sin\left(-x\right)\right] = -\cos\left(-x\right)

Type any function of x; the derivative is computed symbolically in your browser.

Graph of f(x) = sin(-x) and its derivative-3-2-1123-2-1.5-1-0.50.51slope -0.5403f(x)f'(x)tangent at x = 1
Graph of f(x) = sin(-x) and its derivative. The dashed line is the tangent at x = 1; its slope is f'(1) = -0.5403.

How to work it out

  1. 1

    We differentiate f(x)=sin⁡(−x)f(x) = \sin\left(-x\right) with respect to x. The rule that applies is the chain rule.

    f(x)=sin⁡(−x)f(x) = \sin\left(-x\right)
  2. 2

    Chain rule: differentiate the outer function, keep the inside, then multiply by the derivative of the inside. The inside is g(x)=−xg(x) = -x.

    g(x)=−x,g′(x)=−1g(x) = -x,\quad g'(x) = -1
  3. 3

    The outer function is sin(u); its derivative evaluated at g(x), times g'(x):

    f′(x)=[cos⁡(u)]u=g(x)⋅g′(x)f'(x) = \left[\cos\left(u\right)\right]_{u=g(x)} \cdot g'(x)
  4. 4

    Simplify:

    f′(x)=−cos⁡(−x)f'(x) = -\cos\left(-x\right)
  5. 5

    Differentiating once more gives the second derivative, which tells you about curvature:

    f′′(x)=−sin⁡(−x)f''(x) = -\sin\left(-x\right)
LaTeX source of the formulas on this page
\[ \frac{d}{dx}\left[\sin\left(-x\right)\right] = -\cos\left(-x\right) \]
\[ f(x) = \sin\left(-x\right) \]
\[ g(x) = -x,\quad g'(x) = -1 \]
\[ f'(x) = \left[\cos\left(u\right)\right]_{u=g(x)} \cdot g'(x) \]
\[ f'(x) = -\cos\left(-x\right) \]
\[ f''(x) = -\sin\left(-x\right) \]

Values of f and f' for sin(-x)

xf(x)f'(x)
-20.909297430.41614684
-10.84147098-0.54030231
0.5-0.47942554-0.87758256
1-0.84147098-0.54030231
2-0.909297430.41614684
3-0.141120010.9899925

Questions

What is the derivative of sin(-x)?

The derivative of sin⁡(−x)\sin\left(-x\right) is −cos⁡(−x)-\cos\left(-x\right).

What is the second derivative of sin(-x)?

-sin(-x).

Which rule do you use for sin(-x)?

The chain rule.

What is the slope of sin(-x) at x = 1?

-0.54030231.

Related derivatives

    Derivative of sin(-x): -cos(-x) (with steps) | WordGPT