Solution 2.1:3b
From Förberedande kurs i matematik 2
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- | {{ | + | As the integral stands, it is not so easy to see what the primitive functions are, but if we use the formula for double angles, |
- | < | + | |
- | {{ | + | |
+ | <math>\int{2\sin x\cos x}\,dx=\int{\sin 2x}\,dx</math> | ||
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+ | |||
+ | we obtain a standard integral where we can write down the primitive functions directly: | ||
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+ | <math>\int{\sin 2x}\,dx=-\frac{\cos 2x}{2}+C</math> | ||
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+ | |||
+ | where | ||
+ | <math>C</math> | ||
+ | is an arbitrary constant. |
Revision as of 13:41, 17 October 2008
As the integral stands, it is not so easy to see what the primitive functions are, but if we use the formula for double angles,
\displaystyle \int{2\sin x\cos x}\,dx=\int{\sin 2x}\,dx
we obtain a standard integral where we can write down the primitive functions directly:
\displaystyle \int{\sin 2x}\,dx=-\frac{\cos 2x}{2}+C
where
\displaystyle C
is an arbitrary constant.