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matlabmathmaple

integrating and solving for a variable

I want to solve this probability density function f(v)=Av^2e^(-v^2(m/2KT)) integrate it and make it equal to 1 and solve it for A. In Maple:

what i have tried is: 

> restart;
> pdf := v-> Av^2*exp(-(1/2)*mv^2/KT);
> assume(m > 0, K > 0, T > 0);
> g := solve(int(pdf(v), v = 0 .. infinity) = 1, A);

but what i get as an answer is just g:=

Solution

  • Aren't you just missing multiplication symbols between A and v^2, between m and v^2, and between K and T?

    restart;

pdf := v-> A*v^2*exp(-(1/2)*m*v^2/K*T):

assume(m > 0, K > 0, T > 0);

g := solve(int(pdf(v), v = 0 .. infinity) = 1, A);

                        (3/2)       
                   /m T\       (1/2)
                   |---|      2     
                   \ K /            
                   -----------------
                          (1/2)     
                        Pi

    Perhaps you are using Maple's 2D Math input mode and thought that you were getting multiplication of those names implicitly, but are missing the space between names to denote that.

    I couldn't tell whether you wanted brackets around K*T.