Derivative Step-By-Step Calc is an Android app developed by Ivan Petuhov that provides a rapid and detailed solution for the derivative of a function. The app supports any one sign symbols and some functions such as exp, sin, cos, tg, tan, ctan, and other math functions. Users can input functions such as x*sin(a*x), cos(e^(b*x)), exp(1-x*y), (x + a)^n/5^x and more.

The app's interface is user-friendly and easy to navigate. The app provides step-by-step solutions for derivative calculation, which makes it useful for students and professionals alike. The app is free to use and does not require any in-app purchases. Overall, Derivative Step-By-Step Calc is a useful tool for anyone looking for a detailed and rapid solution for derivative calculation.