INVERSE OF A FUNCTION

HI i m looking for a script to inverse numericall a function

i use the function of inverse but not working because the functio is a liitle complicate

y=a*sin(x-ψ)+b*exp(-x/c) a,b,c are constand

thank you

[Alan Stevens]

The right-hand side of your expression will result in an infinite number of values of y, so there won't in general be a unique inverse value. However, if you know the range of values of x that you are interested in then you might be able to get a corresponding value for y using, say, the function fzero.

doc fzero

[george veropoulos]

thank you for your reply

the x is angle from 0 to 180 degree

a graph of y is as follow

how i can use fzero ?

George

Answer 1

[Alan Stevens]

For a gven target value of y you could write a script along the lines of

x0 = initial guess;
x = fzero(@fn, x0);

function z = fn(x)

        a = ...
        b = ...
        etc.
        z = a*sin(x-psi)+b*exp(-x/c) - ytarget; 

end

fzero will return the value of x that makes z equal zero (to within the appropriate tolerance).

[george veropoulos]

I m trying also the mupad and find the many solution

Answer 2

[george veropoulos]

thank you

i have a mistake my relation and i see the the function is not one-one in range from 0:360

is one-to one in range from 0 to 180 degree