Forgot your Texas Instruments TI-83+ the day of a trigonometry exam? Forget about it. Now you can have an iPhone software calculator nestled safely between Pac-Man and Facebook. We checked out four of the App Store’s best graphing calculators to see how well they helped us solve our problems--our math problems at least.

Graphing Calculator

If graphing functionality is all you need, then this free app is worth the download. The graphing calculator plots and traces several equations at a time, supports a plethora of essential equations functions, and can email an image of the graph. The X and Y coordinates are displayed at the top, while pinching the screen zooms in and out of the graph, enabling you to take a closer look at the coordinates. 

We missed an integrated calculator function, and we were limited to plotting only four functions. Graphing Calculator also had a tendency to crash while we were zooming in and out, losing all our data. 

Check out the full review of Graphing Calculator.

Grafly

Grafly is a sensationally vibrant way to graph your equation. This app displays your equation in 2D or 3D with full shading, lighting, and distinction between the inside and the outside of the shape. The 3D graphs are touch-based, tilt-based, and gravity-based; pinch to zoom in and out, calibrate “down” for tilt mode, or, in gravity mode, spin the axis anyway you like by moving your device to get a full, 360 degree view.

This graphing calculator is more suited to calculus geeks than those testing out trigonometry. The graphs can get tricky to navigate and the coordinates are difficult to interpret in 3D mode.

Check out the full review of Grafly.

i41CX+ RPN

The i41CX+ RPN calculator looks and functions just like the graphing calculators that are standard in high school classrooms today, such as the TI-83+ or HP-41C. The interface captures the nostalgia of learning to use a scientific calculator, but only after you take some time to figure out how this app actually works 

This graphing calculator app is suitable for scientific, financial, mathematical, and engineering applications. It supports 319 slots of main memory for data storage and boasts 200 built-in functions, 600 extended memory slots, and over a dozen pre-installed applications, with the ability to add on more. It's also considerably cheaper than investing in an actual scientific calculator, once you own an iPhone or iPod touch.

Check out the full review of i41CX+ RPN.

Calculator AXL - Graphing Calculator

This graphing calculator application has an easy to use interface with its sizeable buttons, customizable background colors, and clear grid lines. However, it can be overwhelming at first, since there's no tutorial or built-in help available.

Unfortunately, the interface gave us difficulty when interpreting coordinates because the graph only counts by 10s, unless you zoom in. But, if done incorrectly, pinching will increase or decrease coordinate values, rather than zooming in and out of the graph.

Check out the full review of Calculator AXL - Graphing Calculator.

THE WINNER
All calculator apps gave us clear graphs that were helpful to find functions' answers. Admittedly, they were also fun to play with; we were entranced by graphing several functions at a time and witnessing the lines draw themselves. The i41CX+ RPN calculator may look rugged and difficult to use, but it is the most concise and packed with the most helpful features. The i41CX+RPN is a reliable emulator of a real graphing calculator, and could help you pass that midterm, after all.