Solving equation with two solutions

I would like to solve for example the equation m*exp(-x m^2/2)=0.2. When you plot this function it should become clear that this has two real solutions, but MATLAB only gives the smallest solution, whereas I need the larger one. Can anyone help me to get the solution for this? I tried adding the inequality M>1 for obtaining the larger value but this has unfortunatly no result.

syms r M;

assume(M,'real')

F = [M*exp(-M^2/2)==0.2, M>1];

solve(F, M)

Thanks a lot!

Answer 1

[Torsten]

syms M
F = M*exp(-M^2/2)==0.2;
vpasolve(F, [1 Inf])

ans = 

2.1872798705256122911063716969905

[renee]

thank you so much! Do you know what I should do to get the analytical largest solution, e.g. for

F = M*exp(-M^2/2)==1/r?

[Torsten]

https://www.wolframalpha.com/input?i=Solve%5BM*Exp%5B-M%5E2%2F2%5D%3Dr%2CM%5D