inline function error help(tanh)

Question

Nathan latchman 2019-4-20

评论： Nathan latchman 2019-4-20

hi,

can anyone help with writing an inline function using tanh, e.g:

fx = inline('((2.*pi^2)./t)-((g*2*pi)./x).*tanh((2*pi*h)./x)');

Answer 1

David Wilson 2019-4-20

I can, but perhaps you should use anonymous functions. The inline approach is now discouraged.

Instead of what you wrote above, try:

fx2 = @(g,h,t,x) ((2.*pi^2)./t)-((g*2*pi)./x).*tanh((2*pi*h)./x)
g= 1;h=2;t=3; 
x = linspace(0,5)';
plot(x, fx2(g,h,t,x))

However going by your chouce of variable names, I'm assuming that g,h, & t are constants, and that x is the variable. In that case try:

g= 1;h=2;t=3; % fold constants in the definition 
fx3 = @(x) ((2.*pi^2)./t)-((g*2*pi)./x).*tanh((2*pi*h)./x)
x = linspace(0,5)';
plot(x, fx3(x))

Is this what you want? Of course f(x=0) returns -inf (for my values of h etc).

Nathan latchman 2019-4-20

thank you David. h and are constants here but i was just using those two to get the program to run i will have to change them to varibles. later on.

I'm trying to make a program to solve false position for that function