Given:
f(x) = 2^x + 1
4.1 Determine the coordinates of the y-intercept of f - NSC Mathematics - Question 4 - 2016 - Paper 1
Question 4
Given:
f(x) = 2^x + 1
4.1 Determine the coordinates of the y-intercept of f.
4.2 Sketch the graph of f, clearly indicating ALL intercepts with the axes as we... show full transcript
Worked Solution & Example Answer:Given:
f(x) = 2^x + 1
4.1 Determine the coordinates of the y-intercept of f - NSC Mathematics - Question 4 - 2016 - Paper 1
Step 1
Determine the coordinates of the y-intercept of f.
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Answer
To determine the y-intercept of the function f(x) = 2^x + 1, we substitute x = 0 into the function:
f(0)=20+1=1+1=2
Therefore, the coordinates of the y-intercept are (0; 2).
Step 2
Sketch the graph of f, clearly indicating ALL intercepts with the axes as well as any asymptotes.
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Answer
The graph of the function f(x) = 2^x + 1 has the following characteristics:
Y-Intercept: (0; 2)
X-Intercept: Since f(x) = 0 has no solution for the equation 2^x + 1 = 0, there is no x-intercept.
Asymptote: The horizontal asymptote occurs at y = 1, as the function approaches y = 1 as x approaches negative infinity.
The graph is an exponential function that increases without bound as x increases, and it approaches y = 1 but never touches it.
Step 3
Calculate the average gradient of f between the points on the graph where x = -2 and x = 1.
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Answer
To find the average gradient between x = -2 and x = 1, we need to calculate the values of f at these points:
f(−2)=2−2+1=41+1=45
f(1)=21+1=2+1=3
Now, we can use the formula for the average gradient:
Average Gradient=1−(−2)f(1)−f(−2)=33−45=3412−45=347=127
Step 4
If h(x) = 3f(x), write down an equation of the asymptote of h.
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Answer
Since the asymptote of f is y = 1, the asymptote of h(x) = 3f(x) will be: