ΣCALCULATORWizard

📈 Graphing Calculator

Plot up to 8 functions on one interactive graph. Polynomials, trig, exponentials, logs, and custom equations. Zoom, pan, export PNG — works perfectly on mobile.

Quick Presets
Custom Function (y =)
Color
 
^ = power  |  * = multiply (2x also works)  |  Functions: sin cos tan ln log sqrt abs asin acos atan  |  Constants: pi e

How to Enter Functions: Syntax and Notation

The graphing calculator uses standard mathematical notation. Exponentiation uses the caret symbol: x^2 means x squared, x^3 means x cubed. Multiplication can be written explicitly (2*x) or implicitly (2x) — the calculator automatically inserts the operator for common patterns. Parentheses control order of operations exactly as in algebra, and nested parentheses like sin(x^2) or e^(-x^2) work correctly. All standard function names are case-insensitive.

Two built-in constants: pi evaluates to 3.14159265… and e evaluates to Euler’s number 2.71828… Trigonometric functions operate in radians — standard for calculus and engineering. To graph in degrees multiply: sin(x*pi/180). Inverse trig is available as asin, acos, and atan.

Polynomial: x^3 - 2*x^2 + x - 1 or x^3-2x^2+x-1 Trig: 2*sin(3*x) + 1 or 2sin(3x)+1 Exponential: e^(-x^2) (bell curve / Gaussian) Logarithm: ln(x+1) (shifted natural log) Rational: (x^2-1)/(x+1) (simplifies to x-1) Absolute value: abs(sin(x)) (rectified sine wave) Damped wave: sin(x)*e^(-x/4)

Reading a Graph: Intercepts, Turning Points, and Asymptotes

X-intercepts are where the curve crosses the x-axis — the roots or zeros of the function, where f(x) = 0. For y = x² − 4 these occur at x = −2 and x = 2. Hover over any point on the curve to see exact (x, y) coordinates. The y-intercept, where the curve crosses the y-axis, equals f(0). For most polynomials this is just the constant term. Local maxima (peaks) and minima (valleys) occur where the derivative equals zero. For y = −x² + 4 the maximum is at (0, 4).

Asymptotes are lines the function approaches but never touches. The function y = 1/x has a vertical asymptote at x = 0 and a horizontal asymptote at y = 0. tan(x) has vertical asymptotes at x = π/2, 3π/2, etc. This calculator automatically inserts null breaks at discontinuities so tan(x) and 1/x render cleanly without false connecting lines through the asymptotes — a major visual quality improvement over basic graphing tools.

Trigonometric Functions: Amplitude, Period, and Phase Shift

The general sinusoidal form y = A × sin(Bx + C) + D has four independent controls. Amplitude A sets the wave height: 3*sin(x) oscillates between −3 and 3. Period controls repetition rate: natural period of sin(x) is 2π ≈ 6.28. Coefficient B modifies this — sin(2x) repeats twice as fast (period π), sin(x/2) repeats half as fast (period 4π). Formula: Period = 2π / |B|. Phase shift C moves the graph horizontally: sin(x − π/2) looks identical to cos(x). Vertical shift D raises or lowers the entire wave.

Use the Trig zoom preset (x: −2π to 2π) to see complete sine and cosine cycles. For visual comparison, graph sin(x), sin(2x), and 2*sin(x) simultaneously in three colors — each demonstrates a different transformation. Comparing them side-by-side makes the abstract transformation rules from a textbook immediately concrete and intuitive.

Polynomials and Function Transformations

Graphing function families side-by-side builds intuition faster than any lecture. Plot y = x, y = x², y = x³, y = x&sup4; simultaneously to see the power family: even powers produce symmetric U-shapes (or W-shapes for quartics), odd powers produce S-shaped curves. Higher even powers are flatter near zero and steeper far from the origin — the difference between x² and x&sup4; is immediately visible on the same axes.

Transformation rules become obvious when graphed. Starting from y = x²: adding 3 gives y = x² + 3, shifting the graph up by 3 units. Replacing x with (x−2) gives y = (x−2)², shifting the vertex right to (2,0). Multiplying by 2 gives y = 2x², narrowing the parabola. Negating gives y = −x², flipping it downward. The composite y = −2*(x−1)² + 3 combines all four: flipped, narrowed, vertex at (1,3). Graphing these in sequence converts abstract rules into immediate visual understanding.

Exponential and Logarithmic Functions

Exponential functions model growth and decay throughout science. When the base exceeds 1, the curve climbs steeply to the right and flattens near zero to the left — e^x models population growth, compound interest, and viral spread. Graph e^x and 2^x together to compare how the base affects growth rate. Replacing x with −x reflects the curve: e^(−x) models radioactive decay, drug concentration, and exponential cooling. The Gaussian bell curve e^(−x^2) is foundational to statistics; graph it to see the symmetric hump shape that defines the normal distribution.

Logarithms are the mathematical inverse of exponentials. Graph e^x and ln(x) together — they are mirror images across the line y = x, which you can also plot for confirmation. Both ln(x) and log(x) only exist for x > 0, so the graph only appears to the right of the y-axis. Their growth is remarkably slow: ln(1000) ≈ 6.9, while 1000² = 1,000,000. Plotting logarithmic and polynomial functions on the same axes makes this contrast unmistakable.

Frequently Asked Questions

How do I graph a function?
Type your equation in the input box (x^2 for a parabola, sin(x) for a sine wave, 2x+3 for a line), pick a color, and click Plot. It appears instantly. You can also tap any Quick Preset button — no typing needed. Press Enter in the input box as a keyboard shortcut to plot.
How many functions can I graph at once?
Up to 8 simultaneous functions, each in a different color. This lets you compare entire function families — for example all six trig functions at once, or a polynomial with its first and second derivative plotted alongside it. Remove any function by clicking the × button in the active list.
Does this work on phones and tablets?
Yes — fully optimized for touch. Tap the zoom preset buttons to change the window. Drag one finger to pan around the graph. Tap any curve to see coordinates in the tooltip. The layout adapts from 320px phone screens up to wide desktop displays. No download or app needed.
Why are trig functions in radians? How do I use degrees?
Radians are the standard unit in calculus, physics, and engineering. One full period of sin(x) is 2π ≈ 6.28, which is why the Trig preset sets the x-axis to ±2π. To work in degrees multiply: sin(x*pi/180) evaluates sine at x degrees. So graphing sin(x*pi/180) produces a sine wave with a visible period of 360 instead of 6.28.
How do I find where two functions intersect?
Graph both functions in different colors. Intersection points are where the curves cross. Hover (or tap on mobile) near the crossing to read exact coordinates from the tooltip. Zoom in using Close Up for greater precision. For algebraic confirmation, set the two expressions equal and solve — then verify visually that the intersection coordinates match.
How do I export my graph?
Click Export and choose a format. PNG downloads a high-resolution image (1400×900px at 2× scale) with all function equations and the viewing window automatically labeled — ready to paste into Word, Docs, or a slide deck. SVG is a vector format that scales infinitely without blurring. Copy to Clipboard lets you paste directly into any document. All exports include the function list and are free with no watermarks.
My function isn’t showing on the graph — what’s wrong?
Most likely causes: the curve is outside the current window (try Standard or Wide), a syntax issue (write 2*x or 2x — not 2 x with a space; check that parentheses are balanced), or a domain restriction — ln(x), sqrt(x), and log(x) only exist for positive x and won’t appear on the left half. The error message below the input box gives a specific hint when the expression can’t be evaluated.
'); w.document.close(); setTimeout(function(){w.print();}, 300); return Promise.resolve(); }); }); } /* ── EXPORT DROPDOWN ── */ function toggleExport(e) { e.stopPropagation(); document.getElementById('export-menu').classList.toggle('open'); } function closeExport() { document.getElementById('export-menu').classList.remove('open'); } document.addEventListener('click', function() { closeExport(); }); /* ── ERROR ── */ function showErr(msg) { var el = document.getElementById('fn-error'); if (msg) { el.textContent = '\u26a0 ' + msg; el.classList.add('show'); } else { el.textContent = ''; el.classList.remove('show'); } } /* ── ENTER KEY ── */ document.getElementById('fn-input').addEventListener('keydown', function(e) { if (e.key === 'Enter') { e.preventDefault(); addFunction(); } }); /* ── DEFAULT GRAPH ── */ setTimeout(function() { addPreset('x^2', '#00d4ff'); }, 150);