0-e-x-2-x-2-1-2-2-dx-I-2-D-e-x-2-y-2-x-2-1-2-2-y-2-1-2-2-dA-x-rcos-y-rsin-J-x-y-r-drd-rdrd-D-re-r-2-r-2-cos-2-

Question Number 206773 by MaruMaru last updated on 24/Apr/24

∫_0 ^∞ (e^(−x^2 ) /((x^2 +(1/2))^2 ))dx= I^2 =∫∫_( D) (e^(−x^2 −y^2 ) /((x^2 +(1/2))^2 (y^2 +(1/2))^2 ))dA x=rcos(θ) y=rsin(θ) J=∣((∂(x,y))/(∂(r,θ)))∣drdθ=rdrdθ ∫∫_( D) ((re^(−r^2 ) )/((r^2 cos^2 (θ)+(1/2))^2 (r^2 sin^2 (θ)+(1/2))^2 ))drdθ

$$\int_{\mathrm{0}} ^{\infty} \:\frac{{e}^{−{x}^{\mathrm{2}} } }{\left({x}^{\mathrm{2}} +\frac{\mathrm{1}}{\mathrm{2}}\right)^{\mathrm{2}} }{dx}= \\ $$$${I}^{\mathrm{2}} =\int\int_{\:\boldsymbol{\mathcal{D}}} \:\frac{{e}^{−{x}^{\mathrm{2}} −{y}^{\mathrm{2}} } }{\left({x}^{\mathrm{2}} +\frac{\mathrm{1}}{\mathrm{2}}\right)^{\mathrm{2}} \left({y}^{\mathrm{2}} +\frac{\mathrm{1}}{\mathrm{2}}\right)^{\mathrm{2}} }{dA} \\ $$$${x}={r}\mathrm{cos}\left(\theta\right)\:\:{y}={r}\mathrm{sin}\left(\theta\right) \\ $$$${J}=\mid\frac{\partial\left({x},{y}\right)}{\partial\left({r},\theta\right)}\mid{drd}\theta={rdrd}\theta \\ $$$$\int\int_{\:\boldsymbol{\mathcal{D}}} \:\frac{{re}^{−{r}^{\mathrm{2}} } }{\left({r}^{\mathrm{2}} \mathrm{cos}^{\mathrm{2}} \left(\theta\right)+\frac{\mathrm{1}}{\mathrm{2}}\right)^{\mathrm{2}} \left({r}^{\mathrm{2}} \mathrm{sin}^{\mathrm{2}} \left(\theta\right)+\frac{\mathrm{1}}{\mathrm{2}}\right)^{\mathrm{2}} }{drd}\theta \\ $$

Commented by MaruMaru last updated on 24/Apr/24