3楼: Originally posted by yz457694 at 2016-10-18 18:44:51
条件 不需要括起来

4楼: Originally posted by 8Bit黑白漫 at 2016-10-18 19:24:11
去掉的话，也还是不行...运行不显示结果

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%作图
clear,clc
x=40:70;
P=0.84;
T=0.9;
A0=-2.00755;
B0=124.937;
A1=0.16976;
B1=-7.7165;
A2=-0.003133362;
B2=0.152286;
A3=0.0000197668;
B3=-0.0079509;
C=7.05;
D=-1603.54;
E=-104095.5;
delta=D^2-4*E*(C-log10(P));   
delta=sqrt(delta);
temref=-2*E/(D+delta)-273.15;
y=B0+temref*A0-T+(B1+temref*A1).*x+(B2+temref*A2)*x.^2+(B3+temref*A3)*x.^3;
plot(x,y)

6楼: Originally posted by yz457694 at 2016-10-18 23:34:38
二分法求多项式的零点？这方法不太好吧，我看了看，你赋的初值 第一次运算就做不下去了，f1,f2,f3一直小于零，你把这个区间的图像做出来就发现这个区间根本就没有零点，所以会无限循环下去。

%作图
clear,clc
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