I think the really neat piece of software behind this is maxima (<a href="https://maxima.sourceforge.io/" rel="nofollow">https://maxima.sourceforge.io/</a>), a rather influential computer algebra system of ancient lineage still in use today in more places than you might think.
Shout out to another project by the same creator: <a href="https://www.derivative-calculator.net/" rel="nofollow">https://www.derivative-calculator.net/</a>
Both of these helped me through my undergrad physics degree, especially because of the step-by-step solutions. Without it I wouldn't have learned nearly as much about calculus.
I really like the interactive function graph. Feels lightweight and snappy compared to the usual framework-driven solutions. I wish the author had gone into a bit more detail on how that works.
Integrating is a part of wolfram alpha, e.g <a href="https://www.wolframalpha.com/input?i=integrate+%28sin%28sqrt%28x%29%2Ba%29+*+e%5Esqrt%28x%29%29+%2F+sqrt%28x%29+dx" rel="nofollow">https://www.wolframalpha.com/input?i=integrate+%28sin%28sqrt...</a>