Hello
My syntax:
clear clc
clc
syms x y
expr = log10(x*y)-log10(x)+log10(y);
solve(expr)
has the result: Empty sym: 0-by-1
The sult should be 2*log10(y)
How do I need to change my syntax?
Thank you
MATLAB: Empty sym: 0-by-1 Log
0-by-1loglog 10
Related Solutions
Your equation is
which shows that your equation has no solution.
There is a bug in the Symbolic Math Toolbox that affects release R2014a and prior. The bug causes the "int" function to return an invalid syntax -- it is a mix of MuPAD and MATLAB syntax. Thus, the "solve" function thinks that "x" is an unknown and cannot solve the equation.
1. If the integral is a constant
As a workaround, if integral "I" is a constant, you can numerically approximate its value using the "vpa" function:
>> syms x>> I = int(-(1+1/x)*exp(-1/2*log(x)^2), x, 0.01, 1);>> syms y>> solve(y + vpa(I)*y == 0, y)ans =0 2. If the integral depends on the unknown
If integral "I" depends on "y", you can use the MuPAD "simplify" and "solve" functions with "feval" as follows:
>> syms x y>> f = y + int(-exp(-log(x)^2/2)*(y+ y/x), x, 0.01,1);>> simplify(feval(symengine, 'solve', f, y))ans =0
Best Answer