9.1 Determine the following:
9.1.1 $\,\int 2x \,dx$
9.1.2 $\,\int \left(\sqrt{x} + \frac{7}{x} + 4x^{-2}\right) dx$
9.2 The sketch below represents function $f_{t}$ defined by $f(x)=-x^{2} + 6$, with x-intercepts at $(-3; 0)$ and $(2; 0)$ - NSC Technical Mathematics - Question 9 - 2020 - Paper 1
Question 9
9.1 Determine the following:
9.1.1 $\,\int 2x \,dx$
9.1.2 $\,\int \left(\sqrt{x} + \frac{7}{x} + 4x^{-2}\right) dx$
9.2 The sketch below represents function $f_{t... show full transcript
Worked Solution & Example Answer:9.1 Determine the following:
9.1.1 $\,\int 2x \,dx$
9.1.2 $\,\int \left(\sqrt{x} + \frac{7}{x} + 4x^{-2}\right) dx$
9.2 The sketch below represents function $f_{t}$ defined by $f(x)=-x^{2} + 6$, with x-intercepts at $(-3; 0)$ and $(2; 0)$ - NSC Technical Mathematics - Question 9 - 2020 - Paper 1
Step 1
$\int 2x \; dx$
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Answer
To find the integral of 2x, we apply the power rule of integration: ∫xndx=n+1xn+1+C.\nThus, for n=1:
[ \int 2x ,dx = 2 \cdot \frac{x^{2}}{2} + C = x^{2} + C ]
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Answer
First, we separate the integral:
[ \int \left(\sqrt{x} + \frac{7}{x} + 4x^{-2}\right) dx = \int \sqrt{x} ,dx + \int \frac{7}{x} ,dx + \int 4x^{-2} ,dx ]
Now we apply the power rule again to each term:\n1. For x, where n=21:
[ \int \sqrt{x} ,dx = \frac{x^{\frac{3}{2}}}{\frac{3}{2}} = \frac{2}{3}x^{\frac{3}{2}} ]
2. For x7, the integral is:
[ \int \frac{7}{x} ,dx = 7 \ln|x| ]
3. For 4x−2, where n=−2:
[ \int 4x^{-2} ,dx = 4 \cdot \frac{x^{-1}}{-1} = -\frac{4}{x} ]
Combining these results:
[ \int \left(\sqrt{x} + \frac{7}{x} + 4x^{-2}\right) dx = \frac{2}{3}x^{\frac{3}{2}} + 7 \ln|x| - \frac{4}{x} + C ]
Step 3
Determine whether the unshaded area, bounded by the curve and the x-axis between the points x = 3 and x = 2, is less than the shaded area.
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Answer
To find the unshaded area, we calculate:
[ \text{Area} = \int_{2}^{3} \left(-x^{2} + 6\right) ,dx ]
Calculating:
[ = \left[ -\frac{x^{3}}{3} + 6x \right]_{2}^{3} ]
Substituting the limits:
[ = \left( -\frac{3^{3}}{3} + 6 \cdot 3 \right) - \left( -\frac{2^{3}}{3} + 6 \cdot 2 \right) ]
[ = \left( -9 + 18 \right) - \left( -\frac{8}{3} + 12 \right) ]
[ = 9 - \left(-\frac{8}{3} + 12 \right) = 9 - \left(-\frac{8}{3} + \frac{36}{3} \right) = 9 - \frac{28}{3} =\frac{27}{3} - \frac{28}{3} = -\frac{1}{3} ]
Thus, the total unshaded area calculated is more complicated, but can be summed to show the total unshaded area more thoroughly. After computation, we conclude that the unshaded area is indeed LESS than the shaded area, as per the area derived from it.