Bepaal $f'\left(x\right)$ vanuit eerste beginsels indien dit gegee word dat $f\left(x\right)=4-7x$ - NSC Mathematics - Question 7 - 2019 - Paper 1
Question 7
Bepaal $f'\left(x\right)$ vanuit eerste beginsels indien dit gegee word dat $f\left(x\right)=4-7x$.
Bepaal $\frac{dy}{dx}$ indien $y=4x^{4}+\sqrt{x}$.
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Worked Solution & Example Answer:Bepaal $f'\left(x\right)$ vanuit eerste beginsels indien dit gegee word dat $f\left(x\right)=4-7x$ - NSC Mathematics - Question 7 - 2019 - Paper 1
Step 1
Bepaal $f'\left(x\right)$ vanuit eerste beginsels indien dit gegee word dat $f\left(x\right)=4-7x$
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Answer
Om f′(x) te bepaal, begin ons met die definisie van die afgeleide: f′(x)=limh→0hf(x+h)−f(x)
Hier is f(x+h)=4−7(x+h) en f(x)=4−7x.
Substitueer in die limiet: f′(x)=limh→0h(4−7(x+h))−(4−7x)
Simpliceer: =limh→0h−7h=−7
Dus, f′(x)=−7.
Step 2
Bepaal $\frac{dy}{dx}$ indien $y=4x^{4}+\sqrt{x}$
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Answer
Om dxdy te bepaal, gebruik die afgeleide van elke term: dxdy=16x3+21x−21
Hierdie afgeleide is gebasseer op die reëls van afgeleides soos dxdxn=nxn−1.
Step 3
Bepaal: $\frac{dy}{dx}$ en $\frac{dy}{da}$ gegee: $y=ax^{2}+a$
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Answer
7.3.1 dxdy=2ax+0=2ax
7.3.2 dady=x2+1
Step 4
Die kurwe met vergelyking $y=\frac{x+12}{x}$ gaan deur die punt $A\left(2;b\right)$.
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Answer
Om die waarde van b te vind waar x=2: b=22+12=7
Die gradient van die kurwe is: ml=dxdy=x2−12
bij x=2: ml=22−12=−13=−3
Die gradient van die loodregte lyn: mperp=−ml1=31
Die vergelyking van die loodregte lyn kan gegee word as: y−7=31(x−2)
Dus sal die uiteindelike vergelyking wees: y=31x+319.