Tangent definition and graph
Drag point "t" to see the construction of the tangent function. Why does tan have period π? Why is tan undefined at π/2?
The Transformations of the Parabola - 'k'
Trig Functions Marc Santos
Sampling Distribution of a Proportion
#2 page 445
Centres in a Triangle
Arches (Parabola, Catenary, Circular)
Geometry Rotational Symmetry