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Category: Integration

Question-89384

Question Number 89384 by nimnim last updated on 17/Apr/20 Commented by mathmax by abdo last updated on 17/Apr/20 $${let}\:{try}\:{another}\:{way}\:\:{we}\:{consider}\:{the}\:{diffeomorphism} \\ $$$$\left({u},{v}\right)\rightarrow\left({x},{y}\right)\:/{x}−{y}={u}\:{and}\:{x}+{y}\:={v}\:\Rightarrow{x}\:=\frac{{u}+{v}}{\mathrm{2}}\:{andy}=\frac{−{u}+{v}}{\mathrm{2}} \\ $$$$\Rightarrow\varphi\left({u},{v}\right)=\left(\varphi_{\mathrm{1}} \left({u},{v}\right),\varphi_{\mathrm{2}} \left({u},{v}\right)\right)=\left({x},{y}\right)=\left(\frac{{u}}{\mathrm{2}}+\frac{{v}}{\mathrm{2}},−\frac{{u}}{\mathrm{2}}+\frac{{v}}{\mathrm{2}}\right)…

0-e-2x-cos-3x-sin-4x-

Question Number 89382 by M±th+et£s last updated on 17/Apr/20 $$\int_{\mathrm{0}} ^{\infty} {e}^{−\mathrm{2}{x}} \:{cos}\left(\mathrm{3}{x}\right)\:{sin}\left(\mathrm{4}{x}\right) \\ $$ Commented by mathmax by abdo last updated on 17/Apr/20 $${cos}\left(\mathrm{3}{x}\right){sin}\left(\mathrm{4}{x}\right)\:={cos}\left(\mathrm{3}{x}\right){cos}\left(\frac{\pi}{\mathrm{2}}−\mathrm{4}{x}\right)…

sin-101x-sin-99-xdx-

Question Number 23830 by anunil1234 last updated on 07/Nov/17 $$\int\mathrm{sin}\left(\mathrm{101x}\right)\mathrm{sin}^{\mathrm{99}} \mathrm{xdx} \\ $$ Commented by prakash jain last updated on 07/Nov/17 $$\mathrm{sin}\:\left(\mathrm{100}{x}+{x}\right)\mathrm{sin}^{\mathrm{99}} {x} \\ $$$$=\mathrm{sin}\:\left(\mathrm{100}{x}\right)\mathrm{cos}\:{x}\mathrm{sin}^{\mathrm{99}}…

1-x-x-1-3-

Question Number 89362 by cindiaulia last updated on 17/Apr/20 $$\int\frac{\mathrm{1}}{\:\sqrt{\mathrm{x}}\left(\sqrt{\mathrm{x}}+\mathrm{1}\right)^{\mathrm{3}} } \\ $$ Commented by jagoll last updated on 17/Apr/20 $${u}\:=\:\mathrm{1}+\sqrt{{x}}\:\Rightarrow\:{du}\:=\:\frac{{dx}}{\mathrm{2}\sqrt{{x}}}\: \\ $$$$\int\:\frac{\mathrm{2}\:{du}}{{u}^{\mathrm{3}} }\:=\:\int\:\mathrm{2}{u}^{−\mathrm{3}} \:{du}\:=\:−{u}^{−\mathrm{2}}…

Integrate-1-8-x-x-2-3-x-dx-

Question Number 154876 by Mr.D.N. last updated on 22/Sep/21 $$\:\:\boldsymbol{\mathrm{Integrate}}: \\ $$$$\:\:\:\int_{\mathrm{1}} ^{\:\mathrm{8}} \:\:\frac{\:\sqrt{\boldsymbol{\mathrm{x}}}−\boldsymbol{\mathrm{x}}^{\mathrm{2}} }{\overset{\mathrm{3}} {\:}\sqrt{\boldsymbol{\mathrm{x}}}}\:\boldsymbol{\mathrm{dx}} \\ $$ Answered by MJS_new last updated on 22/Sep/21…