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# Edexcel A2 C3 Mathematics 12th June 2015 watch

1. maximum is the positive value of R
minimum is the negative value of R

(Original post by tajanamckenzie)
someone help! ok so with the Rcos(x+a) for example and say you find out a and cos then it says work out the minimum value and the smallest possible value of x? Also for when it asks for the maximum and greatest possible value???? and what about for sine graph??? please help
2. (Original post by Nurishment)
But the domain is less than or equal to 0, therefore f(x) can never take the value of 7 because the only time it's 7 is when x = 2. Is there a mark scheme or something?
https://07a69ccf283966549a9350d1a669...%20Edexcel.pdf

it's the first question
3. if sec^2 x is 5 and domain is -pi/2 to 0, how do you know whether sec x is root 5 or -root 5?
4. The domain states the limits of the graph, from -pi/2 to 0. This means that the root cannot be positive, so the only possible answer is a negative one, and in this case it is -root5

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5. hey can anyone help me. for the past paper 2014 C3

Q7 b) cotx = root3

why is there only 2 solutions to this? Can you not take cosx out instead of just dividing it out of the equation? I solved cosx = 0 and tanx = 1/root3 and got 4 solutions.

Mark scheme gives 2 soltuions. (Using just the tanx = 1/root3)
6. Hey guys just need some clarification,if you get less than 40 in c3 or c4, say 34 UMS, does that still get counted towards the overall grading or is it 0?

And just before you judge, I only need 34 UMS to get an A, so I want to see wheter I can afford to not revise much in this subject

Thanks )
7. (Original post by shanee44)
The domain states the limits of the graph, from -pi/2 to 0. This means that the root cannot be positive, so the only possible answer is a negative one, and in this case it is -root5

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It was root 5 according to the answer..it's 6c in the c3 practice paper in the text book
8. (Original post by dandroff)
hey can anyone help me. for the past paper 2014 C3

Q7 b) cotx = root3

why is there only 2 solutions to this? Can you not take cosx out instead of just dividing it out of the equation? I solved cosx = 0 and tanx = 1/root3 and got 4 solutions.

Mark scheme gives 2 soltuions. (Using just the tanx = 1/root3)
Why cosx = 0?
9. (Original post by Anon-)
Why cosx = 0?

rearrange to make root3 sinx - cosx = 0
then take the cos x out

10. Ah, I see. You said the domain was x<=0, not x>=0. If it was how you typed it out, the range would have been g:x>=11 but since it's x>=0 it's g:x>=7 (since it's on the other side of the graph). Next time, please be more wary about what you're typing :P post a picture if you don't want to type it out next time.
11. How would I sketch root(x+2)?
12. (Original post by BBeyond)
How would I sketch root(x+2)?
Step 1. Learn the Graph of Root(x)
Step 2. Set f(x) = Root(x)
Step 3. Inspect
Step 4. f(x+2) = Root(x+2)
Step 5. Realise you just have to shift it two units to the left (C1 work)
Step 6. Profit

Or you could just inspect it and do all of that in your head to see what you need to do but working by steps on paper is easier on your brain anyway

Edit: A way of remembering the Root(x) graph is just to think of the quadratic graph of y=x^2 tumbling to the right (with no negative x values because you can't square root a negative number). Also, always use the y=0 and x=0 methods to work out where a graph crosses the x and y axis respectively.
13. (Original post by BBeyond)
How would I sketch root(x+2)?
root(x) is the inverse of x^2, so we flip the x^2 graph in the line y=x and cut off the bottom half (functions cannot be one-to-many, remember).

f(x+2) is f(x) shifted 2 units to the left, so we do that to the y=root(x) graph and we're done. Try checking your answers on wolfram, it's quite good for this sort of thing
14. What is the relationship between Inx and log?
Attached Images

15. (Original post by Krollo)
root(x) is the inverse of x^2, so we flip the x^2 graph in the line y=x and cut off the bottom half (functions cannot be one-to-many, remember).

f(x+2) is f(x) shifted 2 units to the left, so we do that to the y=root(x) graph and we're done. Try checking your answers on wolfram, it's quite good for this sort of thing
Yeah this was the lines I was along but I stupidly assumed I just had to reflect y=(x-2)^2 in the line y=x rather than y=x^2 - 2
16. (Original post by alexboulton)
What is the relationship between Inx and log?
ln x = log of x to base e, so to do that question you'd have to use the change of base rule, I presume.
17. (Original post by dandroff)
rearrange to make root3 sinx - cosx = 0
then take the cos x out
What do you mean take the cosx out? You can't really do much after sqrt(3)sinx - cosx = 0
18. the way im sacrificing c3 until tomorrow cos I have had a biology exam yesterday and going to have a chemistry exam tomorrow........help lol
19. (Original post by alexboulton)
What is the relationship between Inx and log?
is it 2 to the power of y?

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