## Calculus For Dummies, 2nd Edition (2014)

### Part VI. The Part of Tens

### Chapter 21. Ten Things to Forget

This is without question the easiest chapter in the book. There’s nothing to study, nothing to comprehend, nothing to learn. Just kick back, crank up the music, and *forget* this stuff.

* — Wrong!*

Don’t confuse this with , which is *right.* equals .

* — Wrong!*

Don’t confuse this with , which is *right.* can’t be simplified.

*Slope = — Wrong!*

This is upside down. Slope equals .

* — Wrong!*

You can’t cancel the 3*a*s because it’s not a *factor* of the numerator and the denominator. With , however, you *can* cancel the 3*a*s*.*

* — Wrong!*

Pi is a number, not a variable, so is also just a number, and the derivative of any number is zero. Thus, .

*If k Is a Constant, — Wrong!*

You don’t use the product rule here. Constants work like numbers, not variables, so works just like , which equals 3. Thus, . (Extra credit: Do you see why, in fact, the above is not technically wrong?)

*The Quotient Rule Is — Wrong!*

See the second from the last point in __Chapter 20__, “Ten Things to Remember.”

* — Wrong!*

Do you *C* why this is wrong?

* — Wrong!*

The derivative of cosine is *negative* sine, so the derivative of *negative* cosine is sine, and thus .

*Green’s Theorem*

This one’s *right,* but forget trying to remember it.