matlab隐函数画图

clear;clc;h=ezplot('log10((0。036-1。93*y)*(0。0045-y))=-7184/(x+273)+1。79',[400 900 0 0。0045]);set(h,'LineStyle','--','color','r') ;set(gca,'xticklabel',{'700';'740';'780';'820';'860'});set(gca,'xtick',700:40:860);f=@(x,y)(log10((0。036-1。93。*y)。*(0。0045-y))+7184。/(x+273)-1。79);x=700:40:860;xx=zeros(1,length(x));yy=zeros(1,length(x));for i=1:length(x) xx(i)=x(i); yy(i)=fsolve(@(y)f(x(i),y),0); s=['\leftarrowy=',num2str(yy(i))]; text(xx(i),yy(i),s);endxlabel('x');ylabel('y');grid on; 再问： 大神，我想知道由于Y是关于0。0045的两条渐近线，我只想要下一条，并且y轴区间能取到0。006-0。007 以便我所标注的点在图的相对中间部位 应该怎么样删去上面半条渐近线 再答： clear;clc;h=ezplot('log10((0。036-1。93*y)*(0。0045-y))=-7184/(x+273)+1。79',[400 900],[0 0。0045]);C=get(h,'contourMatrix');x1=C(1,2:end);y1=C(2,2:end);% x2=get(h(2),'XData');% y2=get(h(2),'YData');set(h,'LineStyle','--','color','r') ;set(gca,'xticklabel',{'700';'740';'780';'820';'860'});set(gca,'xtick',700:40:860);f=@(x,y)(log10((0。036-1。93。*y)。*(0。0045-y))+7184。/(x+273)-1。79);x=700:40:860;xx=zeros(1,length(x));yy=zeros(1,length(x));for i=1:length(x) xx(i)=x(i); yy(i)=fsolve(@(y)f(x(i),y),0); s=['\leftarrowy=',num2str(yy(i))]; text(xx(i),yy(i),s);endxlabel('x');ylabel('y');grid on;figure;plot(x1,y1');axis([600 900 0 0。007]);grid on;