Mathematics

Mathematics

Problem

Now try these problems. The answers are in Chapter 19. 10. Find drdθ\frac{d r}{d \theta} if r=cos⁡(1+sin⁡θ)r=\cos (1+\sin \theta).
Intuitive explanation

You're differentiating a composite function where rr depends on θ\theta through nested operations—first a sine, then a cosine. The key is recognizing the chain rule: work from the outside in, differentiating the cosine, then multiply by the derivative of its argument (1+sin⁡θ)(1+\sin\theta). Each layer peels back to reveal the next one you need to differentiate.

Intuitive explanation

You're differentiating a composite function where rr depends on θ\theta through nested operations—first a sine, then a cosine. The key is recognizing the chain rule: work from the outside in, differentiating the cosine, then multiply by the derivative of its argument (1+sin⁡θ)(1+\sin\theta). Each layer peels back to reveal the next one you need to differentiate.

Browse the problem library