# Edexcel A2 C3 Mathematics 12th June 2015Watch

This discussion is closed.
3 years ago
#941
(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??
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!!!
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3 years ago
#942
(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)
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3 years ago
#943
(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!
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3 years ago
#944
Good luck to everyone doing C3 on Friday, I'll be doing it too!
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3 years ago
#945
Anyone know a method for sketching exponentials and ln graphs?
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3 years ago
#946
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
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3 years ago
#947
(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
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3 years ago
#948
Just commenting to get updates on thread when people post stuff lol good luck people!!!!

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3 years ago
#949
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.
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3 years ago
#950
(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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3 years ago
#951
(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.
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3 years ago
#952
(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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3 years ago
#953
(Original post by iceangel8)
Anyone know a method for sketching exponentials and ln graphs?
Any exponential curve of the form Nx 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.
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3 years ago
#954
(Original post by Anon-)
Any exponential curve of the form Nx 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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3 years ago
#955
(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
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3 years ago
#956
(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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3 years ago
#957
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.
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3 years ago
#958
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
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3 years ago
#959
(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
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3 years ago
#960
(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
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