Given:
f(x) = tan x and g(x) = cos(x - 45°) for x ∈ [0°; 360°]
5.1 Draw sketch graphs of f and g on the same set of axes on the grid provided in the ANSWER BOOK - NSC Technical Mathematics - Question 5 - 2021 - Paper 2
Question 5
Given:
f(x) = tan x and g(x) = cos(x - 45°) for x ∈ [0°; 360°]
5.1 Draw sketch graphs of f and g on the same set of axes on the grid provided in the ANSWER BOOK... show full transcript
Worked Solution & Example Answer:Given:
f(x) = tan x and g(x) = cos(x - 45°) for x ∈ [0°; 360°]
5.1 Draw sketch graphs of f and g on the same set of axes on the grid provided in the ANSWER BOOK - NSC Technical Mathematics - Question 5 - 2021 - Paper 2
Step 1
5.1 Draw sketch graphs of f and g on the same set of axes
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Answer
To sketch the graphs of the functions, we first identify their key features:
Function f(x) = tan x
Domain: f(x) is undefined at x = 90° + k*180°, where k is any integer.
Asymptotes: Vertical asymptotes occur at x = 90° and x = 270°.
Intercepts: The graph intersects the x-axis at multiples of 180° (0°, 180°, etc.).
Turning Points: The maximum value occurs at 45° and minimum at 225°.
Turning Points: The maximum and minimum values occur at x = 45° (max) and x = 225° (min).
End Points: At x = 0° and x = 360°, the graph returns to 1.
These characteristics are used to accurately draw the graphs of f and g on the same axes, indicating key features such as intercepts and asymptotes.
Graph Illustration
While I cannot illustrate, be sure to draw the tan function with its vertical asymptotes at 90° and 270°, while the cosine function oscillates between 1 and -1 across the x-axis, intersecting at the identified points.
Step 2
5.2.1 f is undefined
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Answer
The function f(x) = tan x is undefined at:
x = 90°
x = 270°
Thus, the values of x for which f is undefined are:
x = 90° and x = 270°.
Step 3
5.2.2 f(x) * g(x) ≤ 0 where x ∈ [90°; 180°]
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Answer
To determine when f(x) * g(x) ≤ 0 in the interval [90°; 180°], we examine the signs of f(x) and g(x) in this range:
Analysis:
For x ∈ (90°, 135°), f(x) is positive and g(x) is negative, thus f(x) * g(x) < 0.
At x = 135°, f(x) is still positive and g(x) is initially at 0, so the product becomes exactly 0.
For x ∈ (135°, 180°), f(x) remains positive and g(x) becomes negative again, making f(x) * g(x) < 0.