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matlabequalitysymbolic-math

Checking Symbolic Equation Equality in Matlab

How can one check if symbolic eq1 is equal to symbolic eq2 in Matlab:

syms a x y
eq1 = a*(x+y)
eq2 = a*x + a*y
Solution

  • You could use simplify on the difference, then logical to test if it is equal to 0:

    eqAreEqual = logical(simplify(eq1-eq2) == 0);

    You could also use simplify on each and isequal for comparison:

    eqAreEqual = isequal(simplify(eq1), simplify(eq2));

    For example:

    >> syms a x y
>> eq1 = a*(x+y);
>> eq2 = a*x + a*y;
>> eqAreEqual = logical(simplify(eq1-eq2) == 0)

eqAreEqual =

  logical

   1  % True!

>> eqAreEqual = isequal(simplify(eq1), simplify(eq2))

eqAreEqual =

  logical

   1  % Also true!