Finding x such that F(x) takes the maximum value   (see the 10 values of F between a and b -
generated in the second window - to decide when to stop the calculation, before rounding errors prevail).
To change the function, open the code and modify the function F(x).
Choose [a,b] where F has a bumb.   With "test" you find 10 values of F from a to b without starting the search for the maximum.
  a = b =  

To change F open the Code and modify F(x)

Save by clicking here (with the right mouse button) the file on your computer
(change the name if you want, but leave ".htm").
At this point you can use it to solve other equations.
Just open the source code, edit F(x), and run "save".
You can repeat this several times. 
                              Functions:
abs(a)     / |a|                            log(a)   / log of a base e
acos(a)    / arc cosine of a                max(a,b)
asin(a)    / arc sine of a                  min(a,b)
atan(a)    / arc tangent of a               pow(a,b) / a to the power b
atan2(a,b) / arc tangent of a/b             random() / random n. in [0,1)
ceil(a)    / integer closest to a not < a   round(a) / integer closest to a 
cos(a)     / cosine of a                    sin(a)   / sine of a
exp(a)     / exponential of a               sqrt(a)  / square root of a
floor(a)   / integer closest to a not > a   tan(a)   / tangent of a
PI         / π
examples