Chapter 11: Problem 33
Graph the curves described by the following functions, indicating the positive orientation. $$\mathbf{r}(t)=t \cos t \mathbf{i}+t \sin t \mathbf{j}+t \mathbf{k}, \text { for } 0 \leq t \leq 6 \pi$$
/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none}
Learning Materials
Features
Discover
Chapter 11: Problem 33
Graph the curves described by the following functions, indicating the positive orientation. $$\mathbf{r}(t)=t \cos t \mathbf{i}+t \sin t \mathbf{j}+t \mathbf{k}, \text { for } 0 \leq t \leq 6 \pi$$
All the tools & learning materials you need for study success - in one app.
Get started for free
Let \(\mathbf{u}=\langle a, 5\rangle\) and \(\mathbf{v}=\langle 2,6\rangle\) a. Find the value of \(a\) such that \(\mathbf{u}\) is parallel to \(\mathbf{v}\) b. Find the value of \(a\) such that \(\mathbf{u}\) is perpendicular to \(\mathbf{v}\)
Direction angles and cosines Let \(\mathbf{v}=\langle a, b, c\rangle\) and let \(\alpha, \beta\) and \(\gamma\) be the angles between \(\mathbf{v}\) and the positive \(x\) -axis, the positive \(y\) -axis, and the positive \(z\) -axis, respectively (see figure). a. Prove that \(\cos ^{2} \alpha+\cos ^{2} \beta+\cos ^{2} \gamma=1\) b. Find a vector that makes a \(45^{\circ}\) angle with \(\mathbf{i}\) and \(\mathbf{j}\). What angle does it make with \(\mathbf{k} ?\) c. Find a vector that makes a \(60^{\circ}\) angle with i and \(\mathbf{j}\). What angle does it make with k? d. Is there a vector that makes a \(30^{\circ}\) angle with \(\mathbf{i}\) and \(\mathbf{j} ?\) Explain. e. Find a vector \(\mathbf{v}\) such that \(\alpha=\beta=\gamma .\) What is the angle?
An ant walks due east at a constant speed of \(2 \mathrm{mi} / \mathrm{hr}\) on a sheet of paper that rests on a table. Suddenly, the sheet of paper starts moving southeast at \(\sqrt{2} \mathrm{mi} / \mathrm{hr} .\) Describe the motion of the ant relative to the table.
Compute the following derivatives. $$\frac{d}{d t}\left(t^{2}(\mathbf{i}+2 \mathbf{j}-2 t \mathbf{k}) \cdot\left(e^{t} \mathbf{i}+2 e^{t} \mathbf{j}-3 e^{-t} \mathbf{k}\right)\right)$$
Diagonals of a parallelogram Consider the parallelogram with adjacent sides \(\mathbf{u}\) and \(\mathbf{v}\) a. Show that the diagonals of the parallelogram are \(\mathbf{u}+\mathbf{v}\) and \(\mathbf{u}-\mathbf{v}\) b. Prove that the diagonals have the same length if and only if \(\mathbf{u} \cdot \mathbf{v}=0\) c. Show that the sum of the squares of the lengths of the diagonals equals the sum of the squares of the lengths of the sides.
What do you think about this solution?
We value your feedback to improve our textbook solutions.