Integral calculus
      The indefinite integral
      Trigonometric integrals
         Trigonometric integrals of the form
          sin (m x) sin (n x) dx,    sin (m x) cos (n x) dx,    cos (m x) cos (n x) dx.
Trigonometric integrals of the form
sin (m x) sin (n x) dx,    sin (m x) cos (n x) dx,    cos(m x) cos (n x) dx,
in these cases we use the following product to sum formulas,
and the addition formulas.
 
Example:  99. Evaluate
 
We can use the above formula 3) or derive it from the addition formulas, thus
Solution: 
Example:  100. Evaluate
Solution: 
Integrals of rational functions containing sine and cosine,  R (sin x, cos x) dx
Integrals of the form
  R (sin x, cos x) dx
where R denotes a rational function of sin x and cos x, can be transformed to a rational function of the new variable t, using substitution  tan (x/2) = t. Then,
therefore, by substituting
In case the integrand expression does not change the sign when both the sine and the cosine functions change the sign, i.e., if 
R (- sin x- cos x or  R (sin x, cos x)
we can use the substitution tan x = t. Therefore,
Calculus contents F
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