MATLAB: Why wont solve work with the simulataneous equations

MATLABsimultaneous equationssolvesystem of equations

this is my script:
clear,clc
syms x u y
solve('2*sind(u)=x','3*sind(y)=x','u+y=65',x,u,y)
output:
??? Error using ==> mupadengine.mupadengine>mupadengine.feval at 144 MuPAD error: Error: cannot differentiate equation [numeric::fsolve]
Error in ==> solve at 77 sol = eng.feval('symobj::solvefull',eqns,vars);
>>
im just trying to solve for length of a line splitting a triangle into 2 right triangles, i know the solution is x = 1.28 because i made the triangle in solidworks

Best Answer

sind is not a known symbolic operation. You need to recode for radians.
solve('2*sin(u*pi/180)=x','3*sin(y*pi)=x','u+y=65',x,u,y)
or better yet,
solve(2*sind(u)==x, 3*sind(y)==x, u+y==65, [x, u, y])
In the future, solve() will no longer accept strings directly for the equations, so you should get into the habit of using symbolic expressions.
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