An appropriate notion for stability studies of dynamical systems with a continuum of equilibria is semistability. One approach to semistability investigation is based on the nontangency between the vector field and the set of equilibria. In this work, we introduce a novel way of verifying nontangency by computing an outer estimate of the direction cone and illustrate its application through two well-known second-order systems. The stable equilibria of both the systems are shown to possess the semistability property.

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