Photomath is a general-purpose math camera solver app that handles elementary school through college math subjects, including algebra, geometry, trigonometry, statistics and calculus. It's got a camera scanner or manual input, immediate answers with multiple solution methods, step-by-step explanations and customizable visualization. It's good for students, parents and teachers who need help with homework or want to learn better.
Another good option is QANDA, an AI-based math learning app that gives you fast and correct answers to a wide range of math questions. That includes AI Solution Search, which lets you photograph math problems and get answers, and a calculator that shows step-by-step solutions with graphics. QANDA also offers 1:1 real-time question and answer sessions with teachers, so it's a good all-purpose learning tool with more than 92 million users around the world.
If you want a bigger library of solved problems, try SnapXam. The app provides step-by-step solutions to a broad range of math problems, including algebra, calculus, differential equations and trigonometry. SnapXam also has tools like a math worksheet generator and a step checker, so it's a good option for anything math-related, with premium access available through iOS and Android apps.
Last, Wolfram|Alpha is a computational knowledge engine that can handle a very broad range of subjects, including advanced math problems. It'll give you step-by-step solutions, plot functions and perform statistical calculations, among other things. That makes it useful for both academic and professional purposes, and it's available through mobile apps and a notebook edition.