The expression
xm(axn+b)p
where m,n,p∈Q and a,b are real non-zero constants is called a differential binomial.
The integrals from a differential binomial have the form
∫xm(axn+b)pdx
They can be solved in elementary functions in three cases (detailed below). In all other cases these integrals cannot be solved in elementary functions. Here are the 3 cases in which the integral (2) is solvable.
1) p∈Z
In this case we take k=LCM(m,n) and we apply the substitution x=tk, this leads us to an integral from a rational function of t.
2) m+1n∈Z
In this case to solve the integral we apply the substitution: axn+b=t. In this case another (rather obvious) second substitution may be needed t=g(u) to arrive at a rational function of u.
3) m+1n+p∈Z
In this case to solve the integral we apply the substitution: a+bx−n=t. In this case another (rather obvious) second substitution may be needed t=g(u) to arrive at a rational function of u.
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