MATLAB: Solving an equation containing sine and cosine

equationtrigonometry

This might sound silly, so please be patient. I am not a complete beginner at Matlab but I seem to be stuck with this small problem: How do I solve for x? The equation is

A*cos(x)+B/sin(x)=C where A,B and C are constants

Thanks in advance.

Best Answer

If you have the symbolic toolbox, use SOLVE:

solve('A*cos(x)+B/sin(x)=C','x')

Related Solutions

MATLAB: How to solve this integration ???

This shows that MATLAB is not able to find a closed-form expression for the integration problem. You can still find the numerical answer by substituting the numeric values of a and b

syms x a b
c = (x*cos(x)*sin(x))/(a^2*cos(x)^2 + b^2*sin(x)^2)^2;
c_int = int(c, x, 0, pi/1);
x = subs(c_int, [a b], [1 2]);

This will give the value of integration at a=1, b=2. Result:

>> x
x =
-pi/12

MATLAB: Convert Differential Equations to Spate Space

In order to convert your equations to a state-space representation, you need to linearise them. This involves taking the Jacobian. I refer you to Linearization of Nonnlinear Systems to guide your efforts. The Symbolic Math Toolbox (that was not available when I encountered this) can likely help you significantly.

There are several other such references that reveal themselves in an Interweb search.

Best Answer

Related Solutions

MATLAB: How to solve this integration ???

MATLAB: Convert Differential Equations to Spate Space

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