Question

matlab解方程

y=1.06615402141683e-5*x^2+0.00898235839599425*x+1535.16643950786
已知y为向量（
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
），求解x。要程序代码

Answer 1

clear all
close all
a=1.06615402141683*exp(-5);
b=0.00898235839599425;
c=1535.16643950786;
y=[-40:10:150]';
ly=length(y);
for k=1:1:ly;
x1(k)=(-b+sqrt(b^2-4*a*(c-y(k))))/(2*a);
x2(k)=(-b-sqrt(b^2-4*a*(c-y(k))))/(2*a);
end
x=[x1' x2'];
x=[-0.625191182025220 - 468.262164273482i -0.625191182025220 + 468.262164273482i
-0.625191182025220 - 466.773405520361i -0.625191182025220 + 466.773405520361i
-0.625191182025220 - 465.279883201568i -0.625191182025220 + 465.279883201568i
-0.625191182025220 - 463.781551296572i -0.625191182025220 + 463.781551296572i
-0.625191182025220 - 462.278363039030i -0.625191182025220 + 462.278363039030i
-0.625191182025220 - 460.770270899756i -0.625191182025220 + 460.770270899756i
-0.625191182025220 - 459.257226569190i -0.625191182025220 + 459.257226569190i
-0.625191182025220 - 457.739180939337i -0.625191182025220 + 457.739180939337i
-0.625191182025220 - 456.216084085167i -0.625191182025220 + 456.216084085167i
-0.625191182025220 - 454.687885245467i -0.625191182025220 + 454.687885245467i
-0.625191182025220 - 453.154532803087i -0.625191182025220 + 453.154532803087i
-0.625191182025220 - 451.615974264612i -0.625191182025220 + 451.615974264612i
-0.625191182025220 - 450.072156239379i -0.625191182025220 + 450.072156239379i
-0.625191182025220 - 448.523024417871i -0.625191182025220 + 448.523024417871i
-0.625191182025220 - 446.968523549415i -0.625191182025220 + 446.968523549415i
-0.625191182025220 - 445.408597419195i -0.625191182025220 + 445.408597419195i
-0.625191182025220 - 443.843188824526i -0.625191182025220 + 443.843188824526i
-0.625191182025220 - 442.272239550386i -0.625191182025220 + 442.272239550386i
-0.625191182025220 - 440.695690344147i -0.625191182025220 + 440.695690344147i
-0.625191182025220 - 439.113480889501i -0.625191182025220 + 439.113480889501i
];