Final Attestation Exam for the B.Ed. in Mathematics 6B01501

Q1. Evaluate $\int \frac{\sin\sqrt{\theta}}{\sqrt{\theta}\cos^3\sqrt{\theta}}\,d\theta$.
Q2. Find where $g(x)=x^2\sqrt{5-x}$ is increasing/decreasing (domain $x\le5$).
Q3. Two vertices in a graph are called adjacent if, and only if, which condition holds?
Q4. A circle of radius $r$ rests on a horizontal line and is tangent to an inclined segment of length $\alpha$ that makes an angle $\theta$ with the horizontal. Express $r$ in terms of $\alpha$ and $\theta$.
Q5. A pond contains $1{,}000{,}000$ gal of water. Water containing $0.01$ g of chemical per gallon flows in at $300$ gal/min, and the well-mixed solution flows out at the same rate. If $y(t)$ is the amount of chemical in the pond (in grams), which differential equation models $y$?
Q6. Water drains from the conical tank at $5$ ft$^3$/min. The cone has height $10$ ft and top radius $4$ ft (see figure). How fast is the water level changing when $h=6$ ft?
Q7. Determine the order of the differential equation and whether it is linear or nonlinear: $\displaystyle \frac{d^3y}{dt^3}+t\frac{dy}{dt}+(\cos^2 t)y=t^3$.
Q8. Healthy eighteen-year-old women have systolic blood pressure mean $120$ mm Hg and standard deviation $12$ mm Hg. A sample of $50$ freshman women on the day of the final exam has average blood pressure $125.2$. To test whether exam stress elevates blood pressure, which option gives the correct hypotheses, test statistic, and conclusion?
Q9. Compute $\begin{bmatrix}8&3&-4\\5&1&2\end{bmatrix}\begin{bmatrix}1\\1\\1\end{bmatrix}$.
Q10. Let $T$ be the congruence modulo 3 relation on $\mathbb{Z}$:
$ m T n \iff 3 \mid (m-n) $.
Which set gives five integers $n$ such that $n T 0$?
Q11. Solve the matrix equation $Ax=b$ for $A=\begin{bmatrix}3&-7&-2\\-3&5&1\\6&-4&0\end{bmatrix}$ and $b=\begin{bmatrix}-7\\5\\2\end{bmatrix}$.
Q12. Find the tangent plane and a normal line to the surface $x^2-xy-y^2-z=0$ at the point $(1,1,-1)$.
Q13. Which parametric equations describe the line through $(1,1,1)$ parallel to the $z$-axis?
Q14. Solve the Cauchy-Euler equation $t^2y^{\prime\prime}+ty^{\prime}+y=0$ for $t>0$.
Q15. Assume the domain is all people, and let $T(x,y)$ mean "$x$ trusts $y$."
Which pair gives a correct formalization and its negation for "Everybody trusts somebody"?
Q16.
A display case contains 35 gems, 10 real diamonds and 25 fake diamonds. Four gems are removed at random, one at a time without replacement. What is the probability that the last gem stolen is the second real diamond among the four stolen?
Q17. A coin is tossed four times. Let
$A$ be the event that exactly two heads appear,
$B$ be the event that heads and tails alternate,
and
$C$ be the event that the first two tosses are heads.
Which subset relation is true?
Q18. Five independent samples are drawn from a normal distribution with known $\sigma$. For each sample, the interval $(\bar y-0.96\cdot \sigma/\sqrt{n},\ \bar y+1.06\cdot \sigma/\sqrt{n})$ is constructed. What is the probability that at least four of the five intervals contain the unknown mean $\mu$?
Q19. A triangle has sides $a=2$ and $b=3$ with included angle $C=60^\circ$. Find the length of side $c$.
Q20. A sequence satisfies
$c_k=c_{k-1}+6c_{k-2}$ for all integers $k\ge 2$,
with $c_0=0$ and $c_1=3$.
Which explicit formula is correct?
Q21. Let $T:\mathbb{R}^3\to\mathbb{R}^2$ be linear with $T(e_1)=(1,3)$, $T(e_2)=(4,-7)$, and $T(e_3)=(-5,4)$. Find the standard matrix of $T$.
Q22. Without solving the problem, determine an interval in which the solution of the initial value problem $y'+(\tan t)y=\sin t$, $y(\pi)=0$, is certain to exist and be unique.
Q23. Find all point(s) on $y=\dfrac{x}{x-2}$ where the tangent line is perpendicular to $y=2x+3$.
Q24. Assume that all matrices mentioned below have appropriate sizes. Which statements are true?

I. If $A$ is a $3\times 3$ matrix with three pivot positions, then there exist elementary matrices $E_1,\ldots,E_p$ such that $E_p\cdots E_1A=I$.
II. If $AB=I$, then $A$ is invertible.
III. If $A$ and $B$ are square and invertible, then $AB$ is invertible and $(AB)^{-1}=A^{-1}B^{-1}$.
IV. If $AB=BA$ and $A$ is invertible, then $A^{-1}B=BA^{-1}$.
V. If $A$ is invertible and $r\ne 0$, then $(rA)^{-1}=rA^{-1}$.
Q25. Let $X$ and $Y$ have joint pdf $f_{X,Y}(x,y)=2e^{-(x+y)}$ on $0\le x\le y$ and $y\ge 0$. Which option is correct for
(a) $P(Y<1\mid X<1)$,
(b) $P(Y<1\mid X=1)$,
(c) $f_{Y\mid X}(y\mid x)$,
and
(d) $E(Y\mid X=x)$?
Q26. Suppose
$
Y_1=8.3,\ Y_2=4.9,\ Y_3=2.6,\ Y_4=6.5
$
is a random sample of size 4 from the two-parameter uniform pdf
$
f_Y(y;\theta_1,\theta_2)=\frac{1}{2\theta_2}, \qquad \theta_1-\theta_2\le y\le \theta_1+\theta_2.
$
Use the method of moments to estimate $\theta_1$ and $\theta_2$.
Q27. Compute $\lim_{x\to 0^{+}}\frac{\sqrt{x}}{\sqrt{\sin x}}$.
Q28. An urn contains 40 red chips and 60 white chips. Six chips are drawn and discarded, and then a seventh chip is drawn. What is the probability that the seventh chip is red?
Q29. Find the volume of the solid enclosed by the cone $z=\sqrt{x^2+y^2}$ between the planes $z=1$ and $z=2$.
Q30. Assume $t>0$. Solve the system $t\mathbf{x}^{\prime}=\begin{pmatrix}2&-1\\3&-2\end{pmatrix}\mathbf{x}$.
Q31. Consider the infinite sequence of shaded right triangles in the accompanying diagram. Find the total shaded area.
Q32. Evaluate $\displaystyle \lim_{x\to 0^+}\frac{\sin x}{\sin\sqrt{x}}$.
Q33. For the equation $2x+y=7$, determine which statements are true:
(I) For all real numbers $x$, there exists a real number $y$ such that the equation is true.
(II) There exists a real number $x$ such that for all real numbers $y$, the equation is true.
Q34. Differentiate with respect to $x$: $y=\ln\left(\frac{(x^2+1)^5}{\sqrt{1-x}}\right)$.
Q35. Find the Wronskian of two solutions of $(\cos t)y^{\prime\prime}+(\sin t)y^{\prime}-ty=0$ without solving the equation.
Q36. Let $\mathbf{u}=\mathbf{i}\times\mathbf{j}$ and $\mathbf{v}=\mathbf{j}\times\mathbf{k}$. Find $\lVert\mathbf{v}\times\mathbf{u}\rVert$ and a unit vector in the direction of $\mathbf{v}\times\mathbf{u}$ (if defined).
Q37. Suppose $H_0:\mu=240$ is tested against $H_1:\mu<240$ at level $\alpha=0.01$ using a sample of size $25$ from a normal distribution with $\sigma=50$. If the true mean is $\mu=220$, what proportion of the time will the procedure fail to recognize that the mean has dropped to $220$?
Q38. Which formula is logically equivalent to $(p \to r) \leftrightarrow (q \to r)$?
Q39. Find the inverse of $\begin{bmatrix}8&6\\5&4\end{bmatrix}$.
Q40. Evaluate $\displaystyle \lim_{x\to 9}\frac{\sin(\sqrt{x}-3)}{x-9}$.