Given:
$f(x) = \tan x$ and $g(x) = \cos(x - 45^\circ)$ for $x \in [0^\circ; 360^\circ]$
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 $g(x) = \cos(x - 45^\circ)$ for $x \in [0^\circ; 360^\circ]$
5.1 Draw sketch graphs of $f$ and $g$ on the same set of axes on the gri... show full transcript
Worked Solution & Example Answer:Given:
$f(x) = \tan x$ and $g(x) = \cos(x - 45^\circ)$ for $x \in [0^\circ; 360^\circ]$
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 $g$
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Answer
To sketch f(x)=tanx, note that the function has vertical asymptotes at x=90∘ and x=270∘. The function is periodic with a shape that approaches infinity near the asymptotes. The x-intercepts occur at x=0∘, x=180∘, etc.
For g(x)=cos(x−45∘), the function has its x-intercepts at x=135∘ and x=315∘ and ranges from -1 to 1. It has no asymptotes. Indicate the turning points at x=45∘ and x=225∘ along with the respective endpoints.
Step 2
5.2.1 $f$ is undefined
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Answer
The function f(x)=tanx is undefined at the vertical asymptotes, which occur at x=90∘ and x=270∘.
Step 3
5.2.2 $f(x)g(x) \leq 0$ where $x \in [90^\circ; 180^\circ]$
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Answer
Within the interval [90∘;180∘], f(x) is negative at 90∘ and becomes zero at 180∘. The values of x satisfying f(x)g(x)≤0 include the interval 90∘<x<135∘ or x=180∘.