A circle and a line Animation Play

A closed curve Student activity Play

A closed curve Whiteboard exercise Play

A closer look at the sine Whiteboard exercise Play

A closer look at the sine, the cosine and the tangent Whiteboard exercise Play

A closer look at the trigonometric ratios Student activity Play

A line and a circle Student activity Play

A normal to a curve Whiteboard exercise Play

A normal to a curve Student activity Play

A staircase Student activity Play

A tangent to a circle Whiteboard exercise Play

A tangent to a circle Student activity Play

A tetrahedron Student activity Play

A triangle and circles Simulation Play

A triangle and circles Student activity Play

Applying double-angle formula for the tangent Whiteboard exercise Play

Applying the equation of the tangent in exercise Whiteboard exercise Play

Applying the equation of the tangent in exercises Student activity Play

Applying the sum and difference identities for the tangent Student activity Play

Applying the sum and difference identities for the tangent Whiteboard exercise Play

Approximate solution of equations Class activity Play

Approximate solution of equations Whiteboard presentation Play

Approximating using the tangent Simulation Play

Are all trigonometric functions really necessary? Student activity Play

Basic periods of trigonometric functions Student activity Play