By Heather Hattori, Richard H. Langley

Part of 1,001 Calculus Practice Problems For Dummies Cheat Sheet

Many people first encounter the following limits in a Calculus textbook when trying to prove the derivative formulas for the sine function and the cosine function. These results aren’t immediately obvious and actually take a bit of work to justify. Any calculus text should provide more explanation if you’re interested in seeing it!