Plotting the left and right side of a tricky equation?

Hi, I am trying to find the intersection betweeen two sides of an equation that include some tricky trigonometric terms by plotting them. My code is as follows:

syms k3
eqn = -0.1925 == -k3*cot(k3*9.415/2)
fplot([lhs(eqn) rhs(eqn)] , [0.05 0.55])

However, the error message I get is "Warning: Failed to initialize symbolic preferences. Error using mupadmex Internal error with symbolic engine. Quit and restart MATLAB."

Having checked on Wolfram Alpha about an approximation of the plots these should look like, I don't understand what the difficulty is. I've obviously missed something mathmatical?

[David Goodmanson]

Hi Harvey, this works in Matlab 2017b.

[Harvey Rael]

Hi David, is there a problem with the 2018 version I am using then, because it definitely hasn't worked on my laptop a few times.

[David Goodmanson]

Yes, I should have said it works in 2017b update 7. Syms and mupad were locking up after certain updates to Windows 10. As Stephan pointed out in his Answer, updates to 2018a [also 2017b] fixed it, and hopefully that will be your experience.

Answer 1

[Stephan]

Hi,

this works also on R2018a:

Try the following:

ver

and find out if you have the actual update - it should be:

MATLAB Version: 9.4.0.902940 (R2018a) Update 4

If not so, update your Matlab by:

Home Tab / Add Ons (little arrow) / Check for Updates / Products

Then try again.

Best regards

Stephan

[Harvey Rael]

Thank you!