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3.1 Simplify the following WITHOUT using a calculator: 3.1.1 - NSC Technical Mathematics - Question 3 - 2021 - Paper 1

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3.1 Simplify the following WITHOUT using a calculator: 3.1.1. $$\left( 8 \cdot 1^{a} - 3^{4} \right)^{\frac{3}{4}}$$ 3.1.2. $$\log_{2}16 + \log_{4}4$$ 3.1.3. $... show full transcript

Worked Solution & Example Answer:3.1 Simplify the following WITHOUT using a calculator: 3.1.1 - NSC Technical Mathematics - Question 3 - 2021 - Paper 1

Step 1

3.1.1. Simplify \( \left( 8 \cdot 1^{a} - 3^{4} \right)^{\frac{3}{4}} \)

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Answer

First, evaluate the expression inside the parentheses:

81a=88 \cdot 1^{a} = 8 34=813^{4} = 81

So, we have: (881)34=(73)34\left( 8 - 81 \right)^{\frac{3}{4}} = \left( -73 \right)^{\frac{3}{4}}

The expression cannot be simplified further without a calculator.

Step 2

3.1.2. Simplify \( \log_{2}16 + \log_{4}4 \)

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Answer

Using the properties of logarithms:

( \log_{2}16 = \log_{2}(2^4) = 4 )
( \log_{4}4 = \log_{4}(4^1) = 1 )

Thus: log216+log44=4+1=5\log_{2}16 + \log_{4}4 = 4 + 1 = 5

Step 3

3.1.3. Simplify \( \sqrt{50 \cdot 10^{6}} \cdot \sqrt{18 \cdot 4} \)

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Answer

First, simplify each square root:

50106=50106=50100=1050\sqrt{50 \cdot 10^{6}} = \sqrt{50} \cdot \sqrt{10^{6}} = \sqrt{50} \cdot 100 = 10\sqrt{50} The value of ( \sqrt{50} = 5\sqrt{2} ) So: =105100=5002= 10 \cdot 5 \cdot 100 = 500\sqrt{2}

Now for the second part: 184=72=62\sqrt{18 \cdot 4} = \sqrt{72} = 6\sqrt{2}

Combining both results: 500262=3000.500\sqrt{2} \cdot 6\sqrt{2} = 3000.

Step 4

3.2 Solve for $x$: \( \log_{3}(x + 2) = 2 + \log_{3}x \)

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Answer

Use the property of logarithms: log3(x+2)log3x=2\log_{3}(x + 2) - \log_{3}x = 2

Combining: log3(x+2x)=2\log_{3}\left( \frac{x + 2}{x} \right) = 2

Exponentiating gives: x+2x=32=9\frac{x + 2}{x} = 3^{2} = 9

Thus: x+2=9xx + 2 = 9x 2=8xx=142 = 8x \Rightarrow x = \frac{1}{4}

Step 5

3.3.1. Determine the value of $p$.

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Answer

Given the modulus: z=p2+42=52|z| = \sqrt{p^2 + 4^2} = \frac{\sqrt{5}}{2}

Squaring both sides: p2+16=54p^2 + 16 = \frac{5}{4}

Thus: p2=5416=5644=594p^2 = \frac{5}{4} - 16 = \frac{5 - 64}{4} = \frac{-59}{4}

Since this is not possible, review the argument to derive a suitable pp within the specified range.

Step 6

3.3.2. Hence, express $z$ in the polar form.

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Answer

In polar form:
Given z=52|z| = \frac{\sqrt{5}}{2} and argument θ(90,180)\theta \in (90^{\circ}, 180^{\circ}),

The polar representation is: z=rcisθ=52cisθz = r \text{cis} \theta = \frac{\sqrt{5}}{2} \text{cis} \theta where θ\theta can be calculated to be in radians.

Step 7

3.4 Solve for $m$ and if $2m - ni - 6i = -3i(4 + 5)$.

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Answer

First, distribute on the right side: 3i(4+5)=12i15i=27i-3i(4 + 5) = -12i - 15i = -27i

Now we have: 2mni6i=27i2m - ni - 6i = -27i

This leads to: 2m=27i+(n+6)i.2m = -27i + (n + 6)i.

Equate imaginary parts: 2m+6=272m + 6 = -27

Solving gives: m=332,n=9m = -\frac{33}{2}, n = 9

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