matlab nonlinear equations

Asked Apr 12 '21 at 16:43

Active Apr 12 '21 at 16:45

Viewed 94 times

my code is:

function F=root4d(x)

W1 = 0.928*(6-0.928)/tan(x(3))*20;
W2 = (6-0.928)*((6-0.928)/(tan(x(3))))/2*20;
F(1)= x(4)*cos(10*pi/180)+x(1)*cos(x(3))-x(2)*sin(x(3));
F(2)= x(4)*sin(10*pi/180)+x(1)*sin(x(3))+x(2)*cos(x(3))-10*(6-0.928)/tan(x(3))-W1-W2;
F(3)= x(1)-x(2)*tan(20*pi/180)-10*(6-0.928)/sin(x(3));
F(4)= diff(x(4),x(3));

and also:

fun = @root4d;
x0 =[0,0,0,0];
x=fsolve(fun,x0)

but it doesn't work. I get:

Error in solver (line 3)
x=fsolve(fun,x0)

Caused by:
    Failure in initial objective function evaluation. FSOLVE cannot continue.

What can I do to solve my system of nonlinear equations?

edited Apr 12 '21 at 16:45

Ander Biguri

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asked Apr 12 '21 at 16:43

Yoel Schvarcz

hum, haven't tested it, but should it not be `fun=@(x)root4d(x)` ? – Ander Biguri Apr 12 '21 at 16:46
hey, thanks. I tested it, and I keep getting the same problem. – Yoel Schvarcz Apr 12 '21 at 16:49
What happens if you do `root4d([0, 0, 0, 0])` (i.e. `root4d(x0)`) – Pranav Hosangadi Apr 12 '21 at 16:50
1

`F(4)= diff(x(4),x(3));` this is the issue. What do you mean here? The second input is the "order" of the `diff`, but that number can not be anything random, of course. In your case, you try `0` as the first value. – Ander Biguri Apr 12 '21 at 16:57

matlab nonlinear equations

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