Edexcel Mathematics: Core C1 6663 17th May 2017 [Exam Discussion]

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(6) The functiont(x) at the pointT(3,18)has gradient1.5t(x). Giventhesecondderivateofthefunctiont(x)is2(3x1) sketchthecurveyt(x)clearlyshowingany points of intersection with the coordinate axes.

(9 marks)

(7) The line l with equation y  ax  b cuts the lines x  2 and x  4 at the pointsAandBwhereyAandyB arepand 2prespectively,p0.

3
The points C and D are the points where the lines x  2 and x  4 cross the coordinate axis. The

trapeziumABCDhasanareaof24. Findthedistancefromtheorigintothepointwherelinelcrosses the x axis.

(6 marks)

Reply 261

GenjiPro

Can someone explain why the last line (root)X = -8 does not have a solution. I was thinking you square -8 to get 64 hence X=64

Reply 262

candol

Original post by GenjiPro

Can someone explain why the last line (root)X = -8 does not have a solution. I was thinking you square -8 to get 64 hence X=64

Because you need two numbers the same that multiply to make -8 (can't be done with real numbers)

Reply 263

GenjiPro

Original post by candol

Because you need two numbers the same that multiply to make -8 (can't be done with real numbers)

What do you mean by that? I think the answer is no value for X rooted would give -8. What do you mean by your statement?

Reply 264

boaconstricta

In sigma questions does anyone know the difference between:

5(Sigma)1 12=4n^2 =Ar

Find the value of 1-5 Ar
and find the value of Un

Reply 265

boaconstricta

Can someone explain this question to me please

Reply 266

wantodothebest

Original post by candol

cant login to question

go onto google and type in C1 mock paper online 2017 and its the second result :smile:

Reply 267

wantodothebest

Original post by GenjiPro

What do you mean by that? I think the answer is no value for X rooted would give -8. What do you mean by your statement?

I think they mean that you can't have a negative root with real numbers? like type in negative root on your calc, its an error.

Negative roots are imaginary numbers which you cover in Further maths

Reply 268

boaconstricta

Original post by GenjiPro

What do you mean by that? I think the answer is no value for X rooted would give -8. What do you mean by your statement?

Think about it: rootx =-8 is what you got
root64 does not =-8 so it's not a solution
Furthermore, no number square rooted can make a negative number

Reply 269

candol

Original post by GenjiPro

What do you mean by that? I think the answer is no value for X rooted would give -8. What do you mean by your statement?

that is exactly what my statement says: (we are in agreement)

eg sqrt 16 = 4 (or -4) since 4 x 4 = 16

sqrt -8 is not possible since no two same real numbers multiplied together make -8

Reply 270

boaconstricta

Original post by boaconstricta

Can someone explain this question to me please

anyone able to do this?

Reply 271

NotKidding

Original post by boaconstricta

Can someone explain this question to me please

Which part are you struggling with? Does it help if I tell you that they've given you the equation for the sum of n values? Look at the "=" sign.

Reply 272

RDKGames

Study Forum Helper

Original post by boaconstricta

Can someone explain this question to me please

(a) Surely it is straight forward??

(b)

a_6=(a_1+a_2+...+a_5+a_6)-(a_1+a_2+...+a_5)

Reply 273

mathshelppp

when theres 100 on top of the sigma
am i supposed to look for a pattern

@RDKGames

(edited 6 years ago)

Reply 274

boaconstricta

Original post by RDKGames

(a) Surely it is straight forward??

I simply don't understand the difference between when it says ar and when it says Un

(edited 6 years ago)

Reply 275

RDKGames

Study Forum Helper

Original post by boaconstricta

For a) does it want me to find the sum of the first 5 terms? Because I don't get the correct answer when I do this.

Yes.

It should be

[12+4(1)^2]+[12+4(2)^2]+...+[12+4(5)^2]

Reply 276

boaconstricta

Original post by RDKGames

Yes.

It should be

[12+4(1)^2]+[12+4(2)^2]+...+[12+4(5)^2]

But the answer in the markscheme is just 12+4x5squared (112) not all of them added together. This is what's confused me.

Reply 277

rayyanbkc

Original post by wantodothebest

Did an online past paper.

Keeping getting this wrong:

1. You intergrate an f'(x) to get f(x). They give you a set of coordinates to get C.

2. They then give you the equation to the normal - i.e 6y + x = 0. Then they tell you to find the coordinate of T.

I have been trying to do it where I get the gradient of -1/6 of the normal and make it equal to the differentiated formula to try and solve for x. This didnt work.

I then tried to make the intergrated formula equal y which is -1/6x , rearrange, then differentiate and try to factorise. No luck.

Do I need to make -1/6 equal 6? Then what?? :frown:

Reply 278

NotKidding

Original post by RDKGames

Yes.

It should be

[12+4(1)^2]+[12+4(2)^2]+...+[12+4(5)^2]

Actually for part a it's just 12+4(5)^2. All you have to do is substitute the value for n.

Reply 279

RDKGames

Study Forum Helper

Original post by boaconstricta

But the answer in the markscheme is just 12+4x5squared (112) not all of them added together. This is what's confused me.

Oops, misread the question... (the amount of C1 questions I've helped with today must be dragging me down...)

Anyway, you just sub in the value of 5 for n.