3、>>symsax;>>limit((1+a/x).^(-2*x),x,inf)ans=exp(-2*a)4、>>symsxy>>z=(x.^2+y.^2)*exp((x.^2+y.^2)/x*y)dxy=diff(diff(z,x),y)5、symsx;>>int(exp((-x.^2)/2),0,1)ans=(2^(1/2)*pi^(1/2)*erf(2^(1/2)/2))/2>>vpa(ans)ans=0.855624391892148803173304620280056、r=solve("x*exp(x)-1","x")r=lambertw(0,1)>>vpa(r)ans=0.567143290409783872999968662210367、symsx;res=dsolve("D2y+2*Dy+2*y-x*exp(-x)","y(0)=0","Dy(0)=0","x")最後一題：clear;x1=-3:0.05:3;y1=8*ones(size(x1))./(x1.^2+4);theta=0:0.05:2*pi;x2=cos(theta);y2=sin(theta);plot(x1,y1,x2,y2)axisequalgridonxlabel("x");ylabel("y");title("Y1和Y2曲線")圖片自己執行一下程式就顯現了
3、>>symsax;>>limit((1+a/x).^(-2*x),x,inf)ans=exp(-2*a)4、>>symsxy>>z=(x.^2+y.^2)*exp((x.^2+y.^2)/x*y)dxy=diff(diff(z,x),y)5、symsx;>>int(exp((-x.^2)/2),0,1)ans=(2^(1/2)*pi^(1/2)*erf(2^(1/2)/2))/2>>vpa(ans)ans=0.855624391892148803173304620280056、r=solve("x*exp(x)-1","x")r=lambertw(0,1)>>vpa(r)ans=0.567143290409783872999968662210367、symsx;res=dsolve("D2y+2*Dy+2*y-x*exp(-x)","y(0)=0","Dy(0)=0","x")最後一題：clear;x1=-3:0.05:3;y1=8*ones(size(x1))./(x1.^2+4);theta=0:0.05:2*pi;x2=cos(theta);y2=sin(theta);plot(x1,y1,x2,y2)axisequalgridonxlabel("x");ylabel("y");title("Y1和Y2曲線")圖片自己執行一下程式就顯現了