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Edexcel A2 C3 Mathematics 12th June 2015

http://gyazo.com/08285872d0df0103cde73e2184be926b

how do i do ii part a? I can get an answer of arcsinx=arsincosy but that is only there allow answer, how would I get the preferred answer of arcsinx=pi/2 - y??

I feel like this may be about drawing the graph - like when you draw arccosx you then can make an expression which takes this into account to express arcsinx - its defo in the book!!!

Reply 941

Gome44

10

Original post by BBeyond

http://gyazo.com/08285872d0df0103cde73e2184be926b

how do i do ii part a? I can get an answer of arcsinx=arsincosy but that is only there allow answer, how would I get the preferred answer of arcsinx=pi/2 - y??

Remember, cos(x)=sin(90- x) :smile:

Reply 942

FKA Stiglitz

10

Original post by ThePrestigeUK

If I work quickly I can get papers done in 1hr
thats my strong point in maths I work fast

but its my downfall in d1 where 1 mistake can cost you 5 marks

Oh right, yeah, but particularly for the Cores you can use that to your strength. Good luck for D1 though!

Reply 943

Emmi12345

10

Good luck to everyone doing C3 on Friday, I'll be doing it too!

Reply 944

iceangel8

14

Anyone know a method for sketching exponentials and ln graphs?

Reply 945

Anon-

6

Question 8c January 2012: how do you find the second solution, 11pi/12? I looked at the examsolutions video:

why does he assume in the quadrant diagram, that pi - theta is the smaller angle? Didn't we just work out that they are both the same? Everything else is basic to understand, but I just don't get why you put pi - theta as the smaller angle rather than theta + pi/6

Reply 946

studentwiz

3

Original post by Anon-

Question 8c January 2012: how do you find the second solution, 11pi/12? I looked at the examsolutions video:

why does he assume in the quadrant diagram, that pi - theta is the smaller angle? Didn't we just work out that they are both the same? Everything else is basic to understand, but I just don't get why you put pi - theta as the smaller angle rather than theta + pi/6

they are the same but you need to work out the red angle and the green angle for your second solution which is 2thetha=5/6pi +pi then divide by 2 thetha=11/12pi

Reply 947

ComputingIsLife

Just commenting to get updates on thread when people post stuff lol good luck people!!!!

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Reply 948

Choudhry Walid

1

Hi,Guys the question is from differentiation chapter in C3.I can solve the question but there is step i can't do in the question. the question is Question = X^3 x (2X + 6)^4Answer : Let U= X^3 and V= (2X+6)^4dU/dX= 2X^2 and dV/dX = 8(2X+6)^3and so, dY/dX= 8X^3 x (2X+6) + 2X^2 x (2X+6)^4Now, How to solve it further?Reference = C3 Edexcel Chapter 8 Differentiation Exercise 8B Question 1C.Please reply as soon as possible. Thanks in advance.

Reply 949

xy0mz

2

Original post by Choudhry Walid

Hi,Guys the question is from differentiation chapter in C3.I can solve the question but there is step i can't do in the question. the question is Question = X^3 x (2X + 6)^4Answer : Let U= X^3 and V= (2X+6)^4dU/dX= 2X^2 and dV/dX = 8(2X+6)^3and so, dY/dX= 8X^3 x (2X+6) + 2X^2 x (2X+6)^4Now, How to solve it further?Reference = C3 Edexcel Chapter 8 Differentiation Exercise 8B Question 1C.Please reply as soon as possible. Thanks in advance.

I think you're supposed to use the formula if y=f(g(x)), differential= f '(g(x))g '(x) on first page in chapter 8

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Reply 950

Choudhry Walid

1

Original post by xy0mz

I think you're supposed to use the formula if y=f(g(x)), differential= f '(g(x))g '(x) on first page in chapter 8

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This question is from exercise 8B. And that f(x) formula is for exercise 8A. In exercise 8B we have to use the product rule.

Reply 951

Anon-

6

Original post by studentwiz

they are the same but you need to work out the red angle and the green angle for your second solution which is 2thetha=5/6pi +pi then divide by 2 thetha=11/12pi

Yeah I get that, but why do you assume that the red angle is pi - theta and not theta + pi/6?

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(edited 8 years ago)

Reply 952

Anon-

6

Original post by iceangel8

Anyone know a method for sketching exponentials and ln graphs?

Any exponential curve of the form N^x will pass through y=1, because N⁰=1. Also if you have a decent calculator, you can input the exponential function and get a table of values, making it much easier to sketch.

Reply 953

gcsestuff

2

Original post by Anon-

Any exponential curve of the form N^x will pass through y=1, because N⁰=1. Also if you have a decent calculator, you can input the exponential function and get a table of values, making it much easier to sketch.

What calculator do you need for this?

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Reply 954

Anon-

6

Original post by gcsestuff

What calculator do you need for this?

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Works on my Casio FX-82 and FX-991ES Plus, I'm sure it can work on others like the TI-36X

Reply 955

gcsestuff

2

Original post by Anon-

Works on my Casio FX-82 and FX-991ES Plus, I'm sure it can work on others like the TI-36X

Is there a video or manual for it with the Casio 991-E's

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Reply 956

Choudhry Walid

1

Hi,Guys the question is from differentiation chapter in C3.I can solve the question but there is step i can't do in the question. the question is Question = X^3 x (2X + 6)^4Answer : Let U= X^3 and V= (2X+6)^4dU/dX= 2X^2 and dV/dX = 8(2X+6)^3and so, dY/dX= 8X^3 x (2X+6) + 2X^2 x (2X+6)^4Now, How to solve it further?Reference = C3 Edexcel Chapter 8 Differentiation Exercise 8B Question 1C.Please reply as soon as possible. Thanks in advance.

Reply 957

topout8848m

5

I assume you are looking for turning points so dy/dx=0

what you already have (you made a mistake - it is 3X^2)

dY/dX= 8X^3 x (2X+6)^3 + 3X^2 x (2X+6)^4 = 0

factorise

X^2 x (2X + 6)^3 x (8X + 3(2X+6))=0
X^2 x (2X + 6)^3 x (8X + 6X+18)=0
X^2 x (2X + 6)^3 x (14X+18)=0

i.e. X=0, X=-3, X=-9/7

let me know if I made a mistake

Reply 958

Anon-

6

Original post by gcsestuff

Is there a video or manual for it with the Casio 991-E's

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Mode → Table input your function here, then use ALPHA → ) to get X. In here put the limits of your X values and then in which increments they should go up in

Reply 959

BBeyond

15

Original post by Anon-

Question 8c January 2012: how do you find the second solution, 11pi/12? I looked at the examsolutions video:

why does he assume in the quadrant diagram, that pi - theta is the smaller angle? Didn't we just work out that they are both the same? Everything else is basic to understand, but I just don't get why you put pi - theta as the smaller angle rather than theta + pi/6

I found it easier to just expand the tan pi-theta to get a quadratic then solve that

Edexcel A2 C3 Mathematics 12th June 2015

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