# Curve Equations

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#1

Hi, this question on an exam paper really threw me. Iโve seen a question like occur once before and I was stuck on that too. Is there a set way to doing these types of questions ?

Also, that was my working for the Question, but in the markscheme, they got a(x+b/2a) .... and so the thing they got outside the bracket was also different. Not sure where they got that 2 from ? As when u divide through by a, you get b/a, not b/2a.
0
3 weeks ago
#2

Hi, this question on an exam paper really threw me. Iโve seen a question like occur once before and I was stuck on that too. Is there a set way to doing these types of questions ?

Also, that was my working for the Question, but in the markscheme, they got a(x+b/2a) .... and so the thing they got outside the bracket was also different. Not sure where they got that 2 from ? As when u divide through by a, you get b/a, not b/2a.

a= -2
b= 12
c= -13

if so what you had to do is form 3 simultaneous equations.

1st - sub the point (3,5) in to the equation of the curve

2nd - sub the point (5,-3) in to the equation of the curve

3rd - differentiate the equations of the curve and sub in 3. Let the differentiated form of the equations = 0 as it at its maximum at that point.

Solve the 3 equations
0
3 weeks ago
#3

a= -2
b= 12
c= -13

if so what you had to do is form 3 simultaneous equations.

1st - sub the point (3,5) in to the equation of the curve

2nd - sub the point (5,-3) in to the equation of the curve

3rd - differentiate the equations of the curve and sub in 3. Let the differentiated form of the equations = 0 as it at its maximum at that point.

Solve the 3 equations
like this
0
#4
Ohhh, thanks a lot mate. Is that what youโd recommend to do all the time with these sorta questions - sub in the points you know and, if it gives a maximum, differentiate and solve for 0, then rearrange and solve the equations to get the Unknownโs ?
0
3 weeks ago
#5
Ohhh, thanks a lot mate. Is that what youโd recommend to do all the time with these sorta questions - sub in the points you know and, if it gives a maximum, differentiate and solve for 0, then rearrange and solve the equations to get the Unknownโs ?
yeah thatโs what iโd do personally. Itโs what makes most sense to me
1
#6

Also, anyone know how to do this question ? Cba making a new thread ahah
0
3 weeks ago
#7
Are you familiar with the change base formula? If so that will be useful here!

Spoiler:
Show
Let log k (7) = n (where n is just some number!). Therefore 7 = k^n Take Ln of both sides, and Ln (7) = n Ln (k)

So n = Ln (7) / Ln (k) and you can do the rest ! Hope that helps.
0
#8
Ah ok, thanks, Iโll keep that in mind.
0
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