Find the Principal Unit Normal Vector N for the Curve $$\mathbf { r } ( t ) = ( 10 + t ) \mathbf { i } + ( 9 + \ln ( \cos t ) ) \mathbf { k } , - \pi / 2 < t < \pi / 2$$

question 2

Multiple Choice

Find the principal unit normal vector N for the curve r(t) .
- $$\mathbf { r } ( t ) = ( 10 + t ) \mathbf { i } + ( 9 + \ln ( \cos t ) ) \mathbf { k } , - \pi / 2 < t < \pi / 2$$

• A) N = (-cos t)i - (ln(cos t))k
• B) N = (cos t)i + (sin t)k
• C) N = (-sin t)i - (cos t)k
• D) N = (-cos t)i - (tan t)k

---

Definitions:

Glycolysis

The metabolic pathway that breaks down glucose to pyruvate, generating energy and pyruvate molecules, occurring in the cytoplasm of cells.

Eukaryotes

Organisms whose cells contain a nucleus and other membrane-bound organelles, including animals, plants, fungi, and protists.

Phosphorylation

The introduction of a phosphate group into an organic molecule. See kinases.

ATP

Adenosine triphosphate, a high-energy molecule used for energy storage and transfer within cells.