Abstract:
Under certain restrictions on the matrix coefficients of the quadratic matrix equation $X^{\mathrm{T}}DX+AX+X^{\mathrm{T}}B+C=0$, solvability conditions for this equation are given, and its relationship with an equation of the form $XAX=B$ is found. Certain specific types of matrix coefficients obeying the above solvability conditions are indicated.
Key words:quadratic matrix equation, symmetric matrix, square root of a matrix, solvability of a matrix equation.