Integral of
The integral of is .
How to work it out
- 1
We want an antiderivative of f(x) = cos(x).
- 2
Method: standard integral.
- 3
That gives the antiderivative; add the constant C because any constant disappears when you differentiate:
- 4
Check by differentiating the answer; you must get the original function back:
- 5
As a definite integral, evaluate the antiderivative at both ends and subtract. Between 0 and π/2:
LaTeX source of the formulas on this page
\[ \int \cos\left(x\right)\,dx = \sin\left(x\right) + C \]
\[ \int \cos\left(x\right)\,dx \]
\[ \frac{d}{dx}\left[\sin\left(x\right)\right] = \cos\left(x\right) \]
\[ \int_{0}^{\frac{\pi}{2}} \cos\left(x\right)\,dx = \Big[\sin\left(x\right)\Big]_{0}^{\frac{\pi}{2}} \approx 1 \]Definite integrals of the same function
| Interval | Value |
|---|---|
| from 0 to π/2 | 1 |
| from 0 to 0.7853981633974483 | 0.70710678 |
Questions
What is the integral of cos(x)?
The integral of is .
Why do we add + C?
Every function F(x) + C has the same derivative, so the antiderivative is only defined up to a constant.
What is the integral of cos(x) from 0 to π/2?
About 1.