\(\frac{sin2 x}{1+cos x}\) \(= \frac{(2sin (\frac{x}{2}) cos \frac{x}{2})^2 }{2cos^2 (\frac{x}{2})} \) \( [sin x = 2sin (\frac{x}{2}) cos (\frac{x}{2}) ; cos x = 2cos^2 (\frac{x}{2}) -1]\)
\(= \frac{4sin^2 \frac{x}{2} cos^2 (\frac{x}{2}) }{ 2cos^2\frac{x}{2}} \)
\(= 2sin^2 (\frac{x}{2})\)
= 1-cos x
∴ ∫\(\frac{sin2 x}{1+cos x}\) dx = ∫(1-cos x)dx
= x - sin x+C
What is the Planning Process?
Given below is the list of the different methods of integration that are useful in simplifying integration problems:
If f(x) and g(x) are two functions and their product is to be integrated, then the formula to integrate f(x).g(x) using by parts method is:
∫f(x).g(x) dx = f(x) ∫g(x) dx − ∫(f′(x) [ ∫g(x) dx)]dx + C
Here f(x) is the first function and g(x) is the second function.
The formula to integrate rational functions of the form f(x)/g(x) is:
∫[f(x)/g(x)]dx = ∫[p(x)/q(x)]dx + ∫[r(x)/s(x)]dx
where
f(x)/g(x) = p(x)/q(x) + r(x)/s(x) and
g(x) = q(x).s(x)
Hence the formula for integration using the substitution method becomes:
∫g(f(x)) dx = ∫g(u)/h(u) du
This method of integration is used when the integration is of the form ∫g'(f(x)) f'(x) dx. In this case, the integral is given by,
∫g'(f(x)) f'(x) dx = g(f(x)) + C