state vectors linear equation Schrödinger equation linear quantum mechanics solutions
For an equation describing a physical phenomenon, the superposition principle states that a combination of solutions to a linear equation is also a solution of it. When this is true the equation is said to obey the superposition principle. Thus, if state vectors f1, f2 and f3 each solve the linear equation on ψ, then ψ = c1 f1 + c2 f2 + c3 f3 would also be a solution, in which each c is a coefficient. The Schrödinger equation is linear, so quantum mechanics follows this.
