The [i]f[/i]([i]x[/i]) function equation of a sinusoid is entered by default in the rectangular (a.k.a. Cartesian) coordinate input box. To its right, the corresponding [i]r[/i]([i]θ[/i]) equation for a polar curve is displayed.[br][br]This construction is intended to help those new to polar coordinates see the connection between the [i]y [/i]values on the rectangular graph (vertical line segments on 0≤x≤2π) and the [i]r[/i] values on the polar graph (line segments radiating outward from origin/pole on 0≤θ≤2π).[br][br]The default polar curve is a "cardioid," but changing the equation will create different types of polar curves.[br][br]This construction allows zooming/panning, and the cyan [color=#00ffff]+[/color] may be dragged to move the polar graph relative to the rectangular graph.[br][br]The "c" slider will be visible as long as a "c" or "C" is present in the formula text (outside of the spelling of operators cos, csc, cot, and ceil).