- You have a homework due next time.
- Quiz at the end of this hour.
-
Examples from 2.3:
- #13, p. 136
- #22
- #48, p. 137
- #58
- #64
- Any questions on section 2.3?
- The derivatives of trig functions rely on some basic
understanding of the circle.
- Radian measure: $RADIANS=\frac{2\pi}{360}DEGREES$. In calculus, we almost always use radians.
- Length of a sector, related to angle subtending
- Definitions of the trig functions
We will derive the derivative of the sine function from the limit definition of the derivative (although we can see the derivative graphically above).
We'll need two important identities in the course of this:
- The Pythagorean theorem: $\sin^2(x)+\cos^2(x)=1$
- The sine of a sum: $\sin(a+b)=\sin(a)\cos(b)+\sin(b)\cos(a)$
Then the derivative of the cosine will be derived in two different ways:
- by relating cosine to sine graphically, and
- by straight limits.
- Examples:
- #7, p. 146
- #26
- #35
- #49