need help with solving a function

[ptc-4701253]

I really got lost here. I am trying to figure out x where X1 is equal to zero.

Here is the file. See what is the issue?

[StuartBruff]

plot it first to see where to look, then give an initial value for x in keeping with where the nearest point to your desired value is.

[RichardJ]

The function is never equal to zero.

[ptc-4701253]

well I need to find x and assume the function equal to zero

so that what I believe ; but could you please explain why it should not be zero

[RichardJ]

If x is real then cosh(x) has a minimum value of 1, when x=0. The function cosh(x) is never equal to zero for real x. If x is allowed to be complex you have a solution, but not if x must be real.

[ptc-4701253]

I am really not following here Richard

I thought the file says that cosh[(beta*L)*(x/L)]

[RichardJ]

cosh("anything") is never equal to zero, if "anything" is real. It does not matter what "anything" is. It could be a simple variable, say x, or it could be a complicated expression, as in your case. There is no real value that the expression will evaluate to that will make cosh("expression") less than 1.

[Fred_Kohlhepp]

This is vibration of a cantilever. The function(s) are supposed to be the mode shape functions. I believe they are mis-typed; rather than "cosh(beta*L)*x/L" should be cosh(beta*L*x/L). But that's not all that's wrong with this equation. A web search yielded many confusing results.

[RichardJ]

In the worksheet, everything is inside the cosh function. I have no idea if that is correct. Too far outside my field!

[Fred_Kohlhepp]

My point is that while the function as supplied cannot cross zero (as you said,) the function should cross zero. For a discussion (which also has problems):

"http://emweb.unl.edu/Mechanics-Pages/Scott-Whitney/325hweb/Beams.htm"