Practicing Success
If $u=\int e^{a x} \sin b x d x$ and $v=\int e^{a x} \cos b x d x$, then $\left(u^2+v^2\right)\left(a^2+b^2\right)=$ |
$2 e^{a x}$ $e^{2 a x}$ $2 e^{2 a x}$ $b x e^{a x}$ |
$e^{2 a x}$ |
We have, $u =\int e^{a x} \sin b x d x$ and $v=\int e^{a x} \cos b x d x$ $\Rightarrow u =\frac{e^{a x}}{a^2+b^2}(a \sin b x-b \cos b x)$ and, $v=\frac{e^{a x}}{a^2+b^2}(a \cos b x+b \sin b x)$ ∴ $\left(u^2+v^2\right)\left(a^2+b^2\right)^2=e^{2 a x}\left(a^2+b^2\right)$ $\Rightarrow \left(u^2+v^2\right)\left(a^2+b^2\right)=e^{2 a x}$ |