mathematical expression from string input

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I want to make a equation solver which will take any type of mathmatical equation as input .and return the roots.For that reason ,first the program need to read the equation.I want to input the equation in string format.then matlab will consider this as a function of x.
for example if i give input as
(sin(sqrt(x)+a) * e^sqrt(x)) / sqrt(x)
Matlab will read this as
and then i will plot the curve ,and the intersecting point with x axis is the solution of the equation.
How to do that?
Thanks in Advance

Accepted Answer

Stephan
Stephan on 17 Apr 2021
Edited: Stephan on 17 Apr 2021
>> fun = str2sym("(sin(sqrt(x)+a) * e^sqrt(x)) / sqrt(x)")
fun =
(e^(x^(1/2))*sin(a + x^(1/2)))/x^(1/2)
>> pretty(fun)
sqrt(x)
e sin(a + sqrt(x))
-------------------------
sqrt(x)
  4 Comments
Md. Ashikur Rahman Any
Md. Ashikur Rahman Any on 18 Apr 2021
The equation has multiple solution.But it only shows one.
How to show multiple solutions as output.
I know there are infinite number of solution.But if i want to get solution in a sfecific range ,how to get that??
Stephan
Stephan on 19 Apr 2021
Make assumptions on x and solve then:
syms x a
fun = str2sym("(sin(sqrt(x)+a) * exp(sqrt(x))) / sqrt(x)")
fun = subs(fun, a, 1)
assume([x>25, x<30])
intersect = solve(fun==0)
fplot(fun,[25,30])
xline(double(intersect),'k--')
yline(0,'k--')

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