Can I have the user input a non linear equation?

I have to take user's input( a non- linear equation, say f(x) ) and plot it against x and find the solutions using different numerical methods. I have tried inline , str2func, @(x) and nothing's working. For example, user should be able to give f(x) = exp(-x) - x = 0 or f(x) = 600x^4 -550x^3 +200x^2 -70 = 0 and the code should plot it and find its solutions ( the solutions' part is easier to handle but I am stuck at the plot thing)

Answer 1

[Torsten]

http://de.mathworks.com/help/matlab/ref/str2func.html

should help.

Best wishes

Torsten.

[Amruth Chundi]

I used this : str = input('Enter the Non-linear Fucntion : ', 's') ; f = str2func(['@(x)' str]);

And errors I got : Undefined function or variable 's'.

Error in Q1 (line 3) f = str2func(['@(x)' str]);