Integral of
The integral of is .
How to work it out
- 1
We want an antiderivative of f(x) = 2x * cos().
- 2
Method: substitution u = x².
- 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 1:
LaTeX source of the formulas on this page
\[ \int 2 x \cos\left(x^{2}\right)\,dx = \sin\left(x^{2}\right) + C \]
\[ \int 2 x \cos\left(x^{2}\right)\,dx \]
\[ \frac{d}{dx}\left[\sin\left(x^{2}\right)\right] = \cos\left(x^{2}\right) 2 x \]
\[ \int_{0}^{1} 2 x \cos\left(x^{2}\right)\,dx = \Big[\sin\left(x^{2}\right)\Big]_{0}^{1} \approx 0.84147098 \]Definite integrals of the same function
| Interval | Value |
|---|---|
| from 0 to 1 | 0.84147098 |
| from 0 to 0.5 | 0.24740396 |
Questions
What is the integral of 2x * cos()?
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 2x * cos() from 0 to 1?
About 0.84147098.