Have you tried using WolframAlpha? If you get the pro subscription (~$66 per year - ~$45 a year for students) you gain access to their step by step solutions and unlimited problem generator. I am currently studying a Masters of Biostatistics (which has a heavy calculus section) and found this service invaluable.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
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