☆ 置換積分 ☆ |
〇 integration by substitution 2023.2-2015.6 Yuji.W ★ |
◇ 2*3=6 Ten(3)=10^3=1000 微分 ; 偏微分 : 積分 $ e^(i*x)=expi(x) |
〓 {計算例}置換積分 〓 ▢ ${(2*x+3)^2*dx} ? ▷ 2*x+3=X と置く 2*dx=dX ${(2*x+3)^2*dx}=(1/2)*${X^2*dX}=(1/6)*X^3=(1/6)*(2*x+3)^3 ${(2*x+3)^2*dx}=(1/6)*(2*x+3)^3+積分定数 ★ ▢ ${(2x+3)*dx/(x^2+3x+2)} ? ▷ x^2+3x+2=X と置く (2*x+3)*dx=dX ${(2x+3)*dx/(x^2+3x+2)} ${(2x+3)*dx/(x^2+3x+2)}=ln|x^2+3x+2|+積分定数 ★ |
〓 {計算例2}置換積分 〓 ▢ ${x*exp(x^2)*dx} ? ▷ x^2=X と置く 2*x*dx=dX ${x*exp(x^2)*dx} ${x*exp(x^2)*dx}=(1/2)*exp(x^2)+積分定数 ★ ▢ ${x^2*exp(x^3+1)*dx} ? ▷ x^3+1=X と置く 3*x^2*dx=dX ${x^2*exp(x^3+1)*dx} ${x^2*exp(x^3+1)*dx}=(1/3)*exp(x^3+1)+積分定数 ★ ▢ ${sin(x)^3*cos(x)*dx} ? ▷ sin(x)=h と置く cos(x)*dx=dh ${sin(x)^3*cos(x)*dx}=${h^3*dh}=(1/4)*h^4=(1/4)*sin(x)^4 ${sin(x)^3*cos(x)*dx}=(1/4)*sin(x)^4+積分定数 ★ |
☆ uzお勉強しよう since2011 Yuji.W |