The Mathematical Ninja pointed out of the window. “I CAN SEE MY CAR MAKING SMOKE!”, he yelled.
The student looked out of the window, said “Oh no!” and then, after a pause. “Hang on, you don’t have a car.”
The Mathematical Ninja smiled. “Correct. But you’ll now remember how to integrate trig functions:
- I - when you’re integrating
- can - starts with C, meaning $\cos$, which integrates to…
- see - starts with S, meaning $\sin$, which integrates to…
- my car - starts with MC, meaning $-\cos$, which integrates to…
- making smoke - starts with MS, meaning $-\sin$.
“And $-\sin$ integrates back to $\cos$?” asked the student.
“Correct. Also, when you’re integrating, you tend to divide - which means $\int \sin(2x) dx$ would be…?”
“Uh… $-\frac{1}{2} \cos(2x)$?” said the student. “Plus a constant!” he added, hurriedly, catching the Mathematical Ninja’s raised eyebrow.