Đọc bản đầy đủ ở đây: https://thuvienvatly.com/forums/index.php?topic=7146 : Can Super chicken solve this integrals?? : mark_bk99 12:25:33 AM Ngày 22 March, 2012 1.[tex]\int \frac{sinxdx}{cos^{2}x\sqrt{3sin2x+cos^{2}x}}[/tex]
2.[tex]\int_{-1}^{1}{\frac{ln(x^{2}+1)dx}{e^{x}+1}}[/tex] : Trả lời: Can Super chicken solve this integrals?? : mark_bk99 03:04:50 PM Ngày 22 March, 2012 I feel so boring that I solve this math myself m:-t mdc-)
1. I= [tex]\int \frac{sinxdx}{cos^{2}\sqrt{3sin2x+cos^{2}x}}[/tex] =[tex]\int \frac{sinxdx}{cos^{2}\sqrt{cos^{2}x(\frac{6sinx}{cosx}+1)}}[/tex] =[tex]\int \frac{sinxdx}{cos^{3}\sqrt{6tanx+1}}[/tex] =[tex]\int \frac{tanxdx}{cos^{2}x\sqrt{6tanx+1}}[/tex] t=tanx-->dt=[tex]\frac{1}{cos^{2}x}[/tex]dx -->[tex]\int \frac{tdt}{\sqrt{6t+1}}[/tex] u=[tex]\sqrt{6t+1}[/tex]-->u 2=6t+1 ->u/3du=dt -->[tex]\int \frac{(u^{2}-1)du}{18}[/tex] -->I...... Number 2 for member hoc-) :-(( |