Tìm nguyên hàm
1. $\int \frac{sinx.cosxdx}{\sqrt{a^{2}sin^{2}x+b^{2}cos^{2}x}}$
2. $\int \frac{dx}{1+\sqrt{2x-1}}$
3. $\int \frac{x^{2}dx}{(x-1)^{100}}$
4. $\int \frac{dx}{x(x^{6}+1)^{2}}$
5. $\int \frac{1-x^4}{x(x^4+1)}dx$
6. $\int \frac{xdx}{\sqrt{1+x^2}.\sqrt{1+\sqrt{1+x^2}}}$
7. $\int \frac{xdx}{2x^2-1+3\sqrt{x^2-1}}$
