Practice Test 1 - Precalculus

20 questions. Answer them in any order, then submit to see your score and every explanation.

  1. A periodic function has maximum value 5 and minimum value −3-3. For the periodic function described, what is the amplitude?​
  2. A hiker walks 66 km due east (direction 0∘0^\circ from the positive xx-axis), then walks 88 km due north (direction 90∘90^\circ). Using the information provided, what are the magnitude and direction of the hiker's resultant displacement (direction as an angle from the positive xx-axis)?
  3. For the system of equations {3x−2y=54x+y=−6\begin{cases} 3x - 2y = 5\\ 4x + y = -6 \end{cases} what is the coefficient matrix AA in Ax=bAx=b (using variable order x,yx, y)?
  4. Given the vector v=⟨3,4⟩\mathbf{v}=\langle 3,4\rangle and scalar multiplication by k=2k=2, what are the components of 2v2\mathbf{v}?
  5. Two concentric circles have radii rr and 3r3r respectively. If the same central angle intercepts an arc of length 1212 on the smaller circle, what is the ratio of the area of the sector on the larger circle to the area of the sector on the smaller circle?
  6. Using both periodicity and symmetry, evaluate sin⁡(−13π6)\sin\left(-\frac{13\pi}{6}\right). (Recall sin⁡(θ+2π)=sin⁡(θ)\sin(\theta+2\pi)=\sin(\theta) and sin⁡(−θ)=−sin⁡(θ)\sin(-\theta)=-\sin(\theta).)​​​
  7. Given the matrix equation [1−325][xy]=[4−1],\begin{bmatrix}1 & -3\\ 2 & 5\end{bmatrix}\begin{bmatrix}x\\ y\end{bmatrix}=\begin{bmatrix}4\\ -1\end{bmatrix}, which system of equations does it represent?
  8. A triangular garden has two sides of lengths 15 m15\text{ m} and 20 m20\text{ m} that meet at an included angle of 45∘45^\circ. Using the given information, what is the area of the triangle?
  9. A rotating object sweeps out an angle θ\theta in standard position starting from the positive xx-axis on a circle of radius r=3r=3. If the intercepted arc length is s=2πs=2\pi, what is the radian measure of θ\theta?
  10. Vector v\mathbf{v} has magnitude 55 and points in some direction on the coordinate plane. What is the magnitude of −3v-3\mathbf{v}?
  11. Using the periodicity property of cosine on the unit circle (one full rotation), what is cos⁡(θ+2π)\cos\left(\theta+2\pi\right)?
  12. In triangle ABCABC, sides a=8a=8 and b=15b=15 and the included angle C=90∘C=90^\circ are given. Which law should be used first to solve this triangle for side cc?
  13. In right triangle △JKL\triangle JKL, ∠L=90∘\angle L = 90^\circ, JL=8JL = 8 in, and KL=15KL = 15 in. Side JKJK is the hypotenuse. Based on the triangle described, what is the exact length of side JKJK?
  14. For vector v=⟨5,0⟩\mathbf{v}=\langle 5,0\rangle and scalar k=12k=\dfrac{1}{2}, what is the effect of multiplying v\mathbf{v} by kk on its length and direction?
  15. Angles are measured in degrees counterclockwise from the positive xx-axis. Vector u\mathbf{u} has magnitude 1010 at direction 0∘0^\circ, and vector v\mathbf{v} has magnitude 1010 at direction 90∘90^\circ. Using the information provided, what is the magnitude of u+v\mathbf{u}+\mathbf{v}? (Direction is not needed.)​
  16. An angle θ\theta is drawn in standard position on the unit circle in the coordinate plane with measure θ=7π6\theta=\frac{7\pi}{6}. The terminal point on the unit circle is P(x,y)P(x,y), where cos⁡(θ)=x\cos(\theta)=x and sin⁡(θ)=y\sin(\theta)=y. For the angle described, what is the value of sin⁡(θ)\sin(\theta)?​​​
  17. Two vectors are given: u⃗=⟨2,3⟩\vec{u}=\langle 2,3\rangle and w⃗=⟨2,3⟩\vec{w}=\langle 2,3\rangle. For the vectors described, which statement about the vector is true?
  18. For vectors u=⟨3,0⟩\mathbf{u}=\langle 3,0\rangle and v=⟨0,4⟩\mathbf{v}=\langle 0,4\rangle, what is the magnitude ∥u+v∥\|\mathbf{u}+\mathbf{v}\|? Give your answer in simplest form.
  19. A circle has circumference C=2πrC=2\pi r, and one full revolution corresponds to 2π2\pi radians. Using the relationship between circumference and radian measure, how does the formula s=rθs=r\theta derive from the proportionality of arc length to angle?​
  20. A boat's velocity relative to the water is ⟨5,0⟩\langle 5,0\rangle m/s and the current's velocity is ⟨0,2⟩\langle 0,2\rangle m/s. Using the vectors given, what are the components of the resultant velocity vresult\mathbf{v}_{\text{result}}?

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