Quick Question - Clean up code

Hi - thanks for your time.

I have the following code:

PO = 0.15;

syms s

Dratio = solve ('0.15=exp(-(pi*s)/(sqrt(1-(s^2))))','s')

However, I'd like the '0.15' in the Dratio equation to be PO but when I do this - matlab returns the value as a long ugly expression of logs instead of 0.51.

Also when the code is used as it currently is (with 0.15 instead of PO) matlab returns a negative answer and a positive one. Is there a way to ignore the negative answer?

Answer 1

[Oleg Komarov]

PO = 0.15;
syms s

Dratio = double(solve(exp(-pi*s/sqrt(1-s^2))-PO));
Dratio(Dratio > 0)

[Steve]

Thanks very much

[Alexander]

You can also declare |s| to be positive:

PO = 0.15;

syms s positive

Dratio = double(solve(exp(-pi*s/sqrt(1-s^2))-PO))

Dratio =

0.5169

[Oleg Komarov]

That's clever! I tried to play around with assume(s > 0) but it didn't work for some reason, didn't know you could use positive.