# SOCP problem help write the constraint

subject to
0.037sqrt(B+C * x)’ * D * (B+C * x))+ E’(B+C * x)<=0

the square root is the problem.

If this is what you mean,
$$\sqrt{(B+Cx)^TD(B+Cx)}$$
then that is simply equal to
$$|F(B+Cx)|_2$$
where F satisfies F^TF=D. In other words, F is a square root of D, such as the symmetric square root returned by the sqrtm function. The Cholesky factor returned by chol will also work, as long as you make sure to get the right-hand factor.

With this rewrite in mind, this just becomes

0.037 * norm(sqrtm(D)*(B+C*x)) + E'*(B+C*x) <= 0

Thanks…using the sqrtm() gives me error because D is positive semidefinite so i decided to go with this

$$0.037 * norm(D^{1/2}(B+Cx)) + E’(B+Cx) <= 0$$

It still satisfies the $$F^{T}F=D$$ .