b2KIT

Trigonometric Function Explorer

Explore sin, cos, tan and their inverses with amplitude, period, phase shift, and vertical shift sliders. Shows transformations live.

Tested tool guide Tested browser tools Checked August 16, 2026

What Trigonometric Function Explorer does, with a checked example

Drag a slider and the curve on the grid redraws while you drag. Pick sine, cosine, tangent, or one of the inverses, then set amplitude, period, phase shift, and vertical shift; the tool plots the transformed function for whatever combination you land on. It is a graphing board, not a solver - you read the consequences of each parameter off the curve. Two things surprise first-time users. Tangent has no amplitude: it has no peaks or troughs, and its period is pi, not 2pi. And the inverses are single-valued: selecting arcsin shows only the principal branch, not every angle with a given sine.

Worked example

A concrete input and expected output from the current implementation.

Input

Function: sin. Sliders: amplitude 2, period pi, phase shift 0, vertical shift 1.

Expected output

Graph of f(x) = 2 sin(2x) + 1: one full cycle every pi units, midline at y = 1, peaks of 3 at x = pi/4 + k*pi and troughs of -1 at x = 3pi/4 + k*pi, so the curve stays between -1 and 3.

A period slider value of pi gives B = 2pi/pi = 2, so the curve completes one cycle between x = 0 and x = pi. Amplitude 2 stretches the sine swing from +/-1 to +/-2, and the vertical shift of +1 lifts the midline from 0 to 1, moving the range to [-1, 3].

How the result is produced

1

How the sliders map to the formula

The graph follows f(x) = A sin(B(x - C)) + D, and the four sliders set A, the period, C, and D. Amplitude A stretches the curve vertically; the period slider sets the distance for one full cycle, so B = 2pi/P; phase shift C slides the curve horizontally; vertical shift D moves the midline. For tangent the same form applies but the period is pi/B, half of sine's.

2

Inverse functions plot principal values

Choosing arcsin, arccos, or arctan switches the graph to the standard inverse curve. arcsin x and arccos x are defined only for x between -1 and 1, and the tool shows the branch returning angles in the principal ranges - [-pi/2, pi/2] for arcsin, [0, pi] for arccos. arctan x accepts any real input and returns values strictly between -pi/2 and pi/2. The sliders still transform these curves.

Good uses

  • Verifying homework: after hand-sketching y = 3 sin(2x) + 1 with period pi and range [-2, 4], set those sliders and compare the on-screen curve with your sketch, turning points included.
  • Teaching the parameter effects: drag the period slider from 2pi down to pi and watch the curve double its cycles, then drag the phase slider to show the whole wave sliding sideways without changing shape.
  • Fitting a seasonal model: for temperature or daylight data with a known high and low, set amplitude to half the gap between them and vertical shift to the average, then adjust phase so the peak lands on the observed month.

Limits and checks

  • Phase-shift sign: in the form A sin(B(x - C)) + D, increasing C moves the graph right, but in the textbook form A sin(Bx + phi) a positive phi moves it left - the shift is -phi/B. Same slider, opposite direction; compare against the formula on screen before trusting a shift.
  • Tangent quirks: tan has no maximum or minimum, so the amplitude slider changes nothing visible, and its period is pi/B, not 2pi/B. A tangent curve set to period 2pi looks like it repeats every 2pi only because it also repeats every pi.
  • Principal values only: the inverse graphs are single branches and never show the full family of solutions. sin x = 0.5 has solutions x = pi/6 + 2k*pi and x = 5pi/6 + 2k*pi, but arcsin shows only the pi/6 branch, which is the only one in [-pi/2, pi/2].

Common questions

Why does the graph shift left when I move the phase slider to the right?

Direction depends on the formula convention. In the form A sin(B(x - C)) + D, increasing C shifts the graph right. In the older form A sin(Bx + phi), increasing phi shifts it left, because the effective shift is -phi/B. If the curve moves the unexpected way, check which form the tool's displayed formula uses before assuming a bug.

Can I use this tool to see all solutions of an equation like sin x = 0.5?

No. The inverse curves it plots are the single principal branches, so arcsin(0.5) shows only pi/6, roughly 0.524. The complete solution family - pi/6 + 2k*pi and 5pi/6 + 2k*pi - cannot be drawn as one function graph, and this tool does not enumerate it. For that, solve analytically or use a general equation solver.

References and verification

The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.

Related Tools