Knowledge Assessment

Complete this formal assessment to evaluate your knowledge of trigonometric relationships, signs, periods, transformations, and asymptotes. Choose an answer for each question and submit at the bottom.

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Review your answers and step-by-step worked solutions below.
Question 1

Evaluating Primary Ratios

In a right-angled triangle, if sin(θ) =

513
and θ is an acute reference angle, what is the exact value of tan(θ)?

Worked Solution:
  • Identify side lengths from the sine ratio:
    sin(θ) =
    OppositeHypotenuse
    =
    513

    Let Opposite = 5 and Hypotenuse = 13.
  • Calculate the adjacent side using the Pythagorean identity:
    Adjacent = √(13² - 5²) = √(169 - 25) = √144 = 12
  • Formulate the tangent ratio:
    tan(θ) =
    OppositeAdjacent
    =
    512
  • Correct Answer: Option C
Question 2

Signs of Ratios Across Quadrants

If cos(θ) > 0 and csc(θ) < 0, in which of the four quadrants does the terminal arm of angle θ lie?

Worked Solution:
  • Deconstruct the given conditions to identify quadrant limits:
    cos(θ) > 0 (positive cosine) occurs in Quadrants I and IV.
    csc(θ) < 0 (negative cosecant/sine) occurs in Quadrants III and IV.
  • Find the intersection of these two sets:
    Only Quadrant IV satisfies both conditions simultaneously.
  • Correct Answer: Option D
Question 3

Calculating Wave Periodicity

Determine the exact period of the horizontal wave represented by the function:
y = tan(3θ)

Worked Solution:
  • Identify the horizontal frequency parameter from the function y = tan(bθ). Here, b = 3.
  • Recall the fundamental period of the parent tangent wave:
    Unlike sine and cosine (which repeat every 360°), the parent tangent function has a fundamental period of 180° (π radians).
  • Apply the period adjustment formula:
    Period =
    180°b
    =
    180°3
    = 60°
  • Correct Answer: Option B
Question 4

Vertical Graph Shifts

Determine the exact absolute minimum value (lowest y-coordinate) reached by the graph of:
y = -4 cos(θ) + 3

Worked Solution:
  • Identify transformational properties from the general equation y = a cos(θ) + d:
    • Midline vertical displacement (d) = 3.
    • Amplitude (|a|) = |-4| = 4.
  • A vertical reflection (negative sign) mirrors the cosine graph over its midline but does not affect the maximum and minimum boundaries.
  • Calculate the minimum boundary point:
    Minimum = Midline - Amplitude
    Minimum = 3 - 4 = -1
  • Correct Answer: Option C
Question 5

Identifying Graph Discontinuities

Which of the following functions exhibits a vertical asymptote precisely at the horizontal angle value θ = 180° (π)?

Worked Solution:
  • Analyze how vertical asymptotes occur in rational trigonometric functions:
    Asymptotes exist where the denominator of the quotient function resolves to zero.
  • Express key functions through primary operations:
    • tan(θ) =
    sin(θ)cos(θ)
    (Asymptotes where cos(θ) = 0)

    • csc(θ) =
    1sin(θ)
    (Asymptotes where sin(θ) = 0)

    • sec(θ) =
    1cos(θ)
    (Asymptotes where cos(θ) = 0)
  • Evaluate the denominators at the specified angle θ = 180°:
    cos(180°) = -1 (Non-zero, so tangent and secant are defined).
    sin(180°) = 0 (Zero, making cosecant undefined).
  • Thus, cosecant yields an asymptote at θ = 180°.
  • Correct Answer: Option B