The teachers’ library›TrigonometryPythagorean identitiessin2θ+cos2θ=1sin2θ+cos2θ=1tanθ=cosθsinθtanθ=sinθcosθ1+tan2θ=sec2θ1+tan2θ=sec2θ1+cot2θ=csc2θ1+cot2θ=csc2θOpen on a new board The board is kept in this browser only, like your other boards. On any board, the Library button adds this too.More in TrigonometrySOH CAH TOAReciprocal trigonometric functionsExact valuesCompound angle formulasDouble angle formulasHalf-angle and power-reducing formulasSum-to-product formulasCofunction and symmetry identitiesGeneral solutions of trigonometric equationsRadians and degrees