Resting one of your forearms on a bench, assume a plank position with a straight line between your head, glutes and heels.

Multiple Angle Formulas: Multiple angles are of the form sin n θ, cos n θ, and tan n θ. Sine, tangent and cosine are the general functions for the multiple angle formula.

This 'Perfect' Ab Workout Hits Your Core From All Angles Train all of the functions of your core to make the most of your six-pack session. By Brett Williams, NASM Published: Jun 08, 2025 10:19 AM EDT ...