# How to explicit a matlab equation by using the symbolic toolbox?

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Giuseppe on 16 Jun 2021
Answered: Paul on 16 Jun 2021
Hi guys, i want to obtain the expression of the velocity V of the following equation without solving the problem "by hand". I've the need to use the expression of V as a matlab function within a simulink project. Is it possbile by using the symbolic toolbox? if yes, how?

Paul on 16 Jun 2021
Looks like there are two solutions for V based on reasonable assumptions:
syms rho V CD0 K W S T positive
syms gamma real
eqn = T == sym(1/2)*rho*V^2*(CD0 + K*(W*cos(gamma)/(sym(1/2)*rho*V^2*S))^2)*S + W*sin(gamma);
sol = solve(eqn,V,'ReturnConditions',true)
sol = struct with fields:
V: [2×1 sym] parameters: [1×0 sym] conditions: [2×1 sym]
sol.V
ans = After you decide which solution is pertinent to your problem, you can generate from sol.V(1) or sol.V(2) a Matlab Function block (doc page) directly in your Simulink model.

R2021a

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