Gegee:
$f(x) = x^2 - 3x - 10$
Los op vir $x$:
1.1.1 $f(x) = 0$
1.1.2 $f(x) < 0$ en stel die oplossing op $n$ getallen voor
Los op vir $x$:
$2x^2 - 11x = -7x$ (korrekt tot TWEE desimale plekke)
Los op vir $x$ en $y$:
$y - x + 1 = 0$ en $y + 7 = x^2 + 2x$
Die formule wat gebruik word om die weerstand in die diagram hieronder te bereken, in 'n stroombaan waar resistors in parallel gekoppel is, word gegee deur:
$$rac{1}{R_p} = rac{1}{R_1} + rac{1}{R_2}$$
- $R_p$ = totale weerstand in ohm $( ext{Ω})$
- $R_1$ = weerstand van resistor 1 in ohm $( ext{Ω})$
- $R_2$ = weerstand van resistor 2 in ohm $( ext{Ω})$
1.4.1 Maak $R_p$ die onderwerp van die formule - NSC Technical Mathematics - Question 1 - 2022 - Paper 1
Question 1
Gegee:
$f(x) = x^2 - 3x - 10$
Los op vir $x$:
1.1.1 $f(x) = 0$
1.1.2 $f(x) < 0$ en stel die oplossing op $n$ getallen voor
Los op vir $x$:
$2x^2 - 11... show full transcript
Worked Solution & Example Answer:Gegee:
$f(x) = x^2 - 3x - 10$
Los op vir $x$:
1.1.1 $f(x) = 0$
1.1.2 $f(x) < 0$ en stel die oplossing op $n$ getallen voor
Los op vir $x$:
$2x^2 - 11x = -7x$ (korrekt tot TWEE desimale plekke)
Los op vir $x$ en $y$:
$y - x + 1 = 0$ en $y + 7 = x^2 + 2x$
Die formule wat gebruik word om die weerstand in die diagram hieronder te bereken, in 'n stroombaan waar resistors in parallel gekoppel is, word gegee deur:
$$rac{1}{R_p} = rac{1}{R_1} + rac{1}{R_2}$$
- $R_p$ = totale weerstand in ohm $( ext{Ω})$
- $R_1$ = weerstand van resistor 1 in ohm $( ext{Ω})$
- $R_2$ = weerstand van resistor 2 in ohm $( ext{Ω})$
1.4.1 Maak $R_p$ die onderwerp van die formule - NSC Technical Mathematics - Question 1 - 2022 - Paper 1
Step 1
1.1.1 $f(x) = 0$
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Answer
To solve for x, we set the quadratic equation to zero:
x2−3x−10=0
Using the quadratic formula:
x=2a−b±b2−4ac
where a=1, b=−3, c=−10. Thus,
x=2(1)−(−3)±(−3)2−4(1)(−10)
Simplifying yields:
x=23±9+40=23±49
Therefore,
x=23+7=5orx=23−7=−2
The solutions for x are 5 and −2.
Step 2
1.1.2 $f(x) < 0$ en stel die oplossing op $n$ getallen voor
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Answer
We need to find the critical points where the function is less than zero. We know the roots are x=−2 and x=5. The intervals to test are:
(−∞,−2)
(−2,5)
(5,∞)
Testing these intervals using a test point from each interval:
For x=−3: f(−3)=9+9−10=8>0
For x=0: f(0)=−10<0
For x=6: f(6)=36−18−10=8>0
Thus, the solution for f(x)<0 occurs in the interval:
Answer: (−2,5)
Step 3
1.2 Los op vir $x$: $2x^2 - 11x = -7x$
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Answer
Rearranging gives:
2x2−4x=0
Factoring out 2x:
2x(x−2)=0
Thus, the solutions are:
x=0orx=2
Step 4
1.3 Los op vir $x$ en $y$: $y - x + 1 = 0$ en $y + 7 = x^2 + 2x$
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Answer
First, solve the linear equation for y:
y=x−1
Substituting y into the quadratic equation:
x−1+7=x2+2x
This simplifies to:
x2+2x−x+8=0⟹x2+x+8=0
Using the quadratic formula:
x=2(1)−1±1−4(1)(8)
This results in complex roots:
x=2−1±−31
Thus,
y=2−1±−31−1
Step 5
1.4.1 Maak $R_p$ die onderwerp van die formule.
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Answer
Starting with the formula:
Rp1=R11+R21
We can rewrite this as:
Rp=R11+R211
Step 6
1.4.2 Bereken vervolgens, andersins, die weerstand $R_p$ as: $R_1 = 40 \text{ Ω}$ en $R_2 = 45 \text{ Ω}$
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Answer
Using the formula derived:
Rp=401+4511
Calculating:
Rp1=401+451=180045+40=180085
Therefore,
Rp=851800≈21.18 Ω