As x increases k increases.A body is said to be in simple harmonic motion only when,F=−kx.....(1) where F is force,k is force constant, andx is displacement of the body from the mean position.Given:F=−kx​ ......(2)On comparing the equations (1) and (2), it can be said that in order to execute simple harmonic motion, k should be proportional to x​ . Thus, as x increases k increases.