possibly serious bug....need someone from HP...

[webmasterpdx]

(11-21-2017 07:35 PM)parisse Wrote:  You are confused: there is a difference between a function f and an expression g. A function has arguments unlike an expression. If f is a function, you can compute f(2) or f(x) and get an expression, while g(2) or g(x) does not mean anything.
Regarding solve, it solves polynomial-like equations, i.e. equations that can be rewritten like a polynomial equation, your equation can not be rewritten like that. For more general equations, there is no method for exact solving, you must switch to approx solving (fsolve). You can solve an expression=another expression with respect to a variable, but solving a function=another function does not mean anything : with respect to what would you solve?. I will add a check to avoid the calc reboot in this situation.

Yes, I was confused. I thought I saw f:=.... and you could then replace x by typing f(x)....but it's not so (just tested it). Thats what happens when you don't have a CAS manual.
However, I could type f=g, as that would create an equation. I missed the line in the help where it says it has to be a polynomial.

So, I tried fsolve, and it worked!

Now, what I'm really trying to do is this.

I'm trying to solve the intersection between the following 2 functions:

f(x):=atan(cot(pi*x))/pi + x -1/2
g(x):=(z^n-x^n)^1/n

The problem specified above was this with z set to 5 and n set to 2.

What I was trying to do was find the x value at the intersection between f(x) and g(x) in terms of z and n.

I can't do this with fsolve, but with csolve(f(x)=g(x),x), I got:

(z^n-e^(i*n*pi))^(1/n)

however, when I evaluate this with z=5, n=2, I get 2*(6)^(1/2), and not 4 (which is the correct answer).

First question is why do I get an incorrect answer and secondly, is there a way to solve this?
Thx