How to solve equations in variable terms?

3 views (last 30 days)
I wanted to find equation solving a, b, c, and d in terms of e, f, g, and h. Is it possible to do this in MATLAB? Here's my code for the moment.
clc
clear all
syms a b c d e f g h alpha
A = [a b; c d];
R = [cos(alpha) -sin(alpha); sin(alpha) cos(alpha)];
D = (R*A)*transpose(R);
e=D(1,1)
e = 
f=D(1,2)
f = 
g=D(2,1)
g = 
h=D(2,2)
h = 
eqn=[e f g h];
solver=solve(eqn,[a b c d])
solver = struct with fields:
a: 0 b: 0 c: 0 d: 0

Accepted Answer

Dyuman Joshi
Dyuman Joshi on 21 Apr 2023
syms a b c d e f g h alpha
A = [a b; c d];
R = [cos(alpha) -sin(alpha); sin(alpha) cos(alpha)];
D = (R*A)*transpose(R);
%Modify the equations
eq1 = e-D(1,1)==0;
eq2 = f-D(1,2)==0;
eq3 = g-D(2,1)==0;
eq4 = h-D(2,2)==0;
eqn=[eq1 eq2 eq3 eq4];
solver=solve(eqn,[a b c d])
solver = struct with fields:
a: (e*cos(alpha)^2 + h*sin(alpha)^2 + f*cos(alpha)*sin(alpha) + g*cos(alpha)*sin(alpha))/(cos(alpha)^2 + sin(alpha)^2)^2 b: (f*cos(alpha)^2 - g*sin(alpha)^2 - e*cos(alpha)*sin(alpha) + h*cos(alpha)*sin(alpha))/(cos(alpha)^2 + sin(alpha)^2)^2 c: (g*cos(alpha)^2 - f*sin(alpha)^2 - e*cos(alpha)*sin(alpha) + h*cos(alpha)*sin(alpha))/(cos(alpha)^2 + sin(alpha)^2)^2 d: (h*cos(alpha)^2 + e*sin(alpha)^2 - f*cos(alpha)*sin(alpha) - g*cos(alpha)*sin(alpha))/(cos(alpha)^4 + sin(alpha)^4 + 2*cos(alpha)^2*sin(alpha)^2)

More Answers (0)

Categories

Find more on Partial Differential Equation Toolbox in Help Center and File Exchange

Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!