Originally posted by eagle:Is there a portion where they asked you to find out what other graphs to draw to solve some equation?
Yup, we were asked to draw another graph. That one was no problem. Then we were told to find the x-coordinate of the intersection point, and the question says:
"This value of x is a solution of the equation x^3 + Ax^2 + Bx + C = 0. Find the value of A, the value of B, and the value of C."
Btw, my x-coordinate was x= 0.45.
-1 for leaving in 3 s.f when question wants 2 d.p
-1 the values of A,B and C, don't know how to do. Haha.
Frankly speaking, even though this paper is manageable, you have to admit that the steps to the answers are rather tedious, and takes up quite a lot of time. Usually I always have spare time for EM, but I finished on the dot this time.
you all never use that calculator that can solve cubic equations meh?
Originally posted by eagle:Is there a portion where they asked you to find out what other graphs to draw to solve some equation?
Something like that, yes.
Originally posted by eagle:you all never use that calculator that can solve cubic equations meh?
But then there's only 1 solution from the graph we get.. because from what I know if there's 3 values straightaway (x-a)(x-b)(x-c). But only one, how to do uh?
Originally posted by eagle:you all never use that calculator that can solve cubic equations meh?
You're supposed to use your graph.
mine is 0.5 nia.
but how did you do it?
what i did was move c to the right and take out x and times 1/5 to both sides.
the - at both sides wld cancel.
so 1/5x( -b - xsquare) = c
c= 2-2x also, cos the line they asked you to draw was y = 2-2x
so 1/5x( -b - xsquare) = c/5
compare wif 1/5x(12 - xsquare) = 2-2x
equate both equations together. You'll get something that equates to 0. Then compare that with the coefficients of the given equation.
Originally posted by davidche:what i did was move c to the right and take out -1/5x
the - at both sides wld cancel.
so 1/5x( -b - xsquare) = c
c= 2-2x also, cos the line they asked you to draw was y = 2-2x
I suddenly see the light.
Originally posted by iamapebble:But then there's only 1 solution from the graph we get.. because from what I know if there's 3 values straightaway (x-a)(x-b)(x-c). But only one, how to do uh?
cubic equation doesn't necessary have 3 real solutions
Originally posted by Vendettus:You're supposed to use your graph.
No one stopping you from using your calculator to verify
sry abit mistake in my explaination. dont take out 1/5x. just take out x and times 1/5 to both sides.
Oh ya hor.. AHH I know already, thanks! :( Nevermind, it's only 1 mark.
If interested, here are rough solutions with workings...
Be so kind as to inform me of any careless mistakes here thanks.
I multiplied both equations together, ended up with a highest x power of 4. Factorised the equation by taking out the x, then used the equation inside the brackers to divide by my value of x, giving me A= 1, B= -12, C= 12.
lol sounds like you are doing a 10 mark qn. This paper i think is set to be difficult because they award less marks for more workings. they asked for value of A B and c man. and it is ONE mark `O`
Originally posted by Theguiltshow:I multiplied both equations together, ended up with a highest x power of 4. Factorised the equation by taking out the x, then used the equation inside the brackers to divide by my value of x, giving me A= 1, B= -12, C= 12.
x power 4? Whoa.
You're wandering far from the path, dude.
YEAH sure wrong la haha I was like wth why am I doing so much just for 1 mark.
Originally posted by Mikethm:If interested, here are rough solutions with workings...
Be so kind as to inform me of any careless mistakes here thanks.
The one on CF, is it 3,7,14,11,5? >< Then mean and SD followed from these values.. Not too sure.
Last question is without replacement, so you can't include 1,1 2,2 3,3 4,4 5,5 and 6,6.
Other than these two my answers are the same (or differ by +/- 0.1) so I assume they should be right.
Originally posted by Mikethm:If interested, here are rough solutions with workings...
Be so kind as to inform me of any careless mistakes here thanks.
Thanks.
i dun really agree with the last part on probability.
There should only be 30 possible outcomes, isnt it?
And we can get the number 4 two times..
YA, i also think the probability answer is wrong. Haha.
And I think that this paper is the most difficult out of A maths p1 and 2, and E maths p1. Argh.
Originally posted by iamapebble:The one on CF, is it 3,7,14,11,5? >< Then mean and SD followed from these values.. Not too sure.
Last question is without replacement, so you can't include 1,1 2,2 3,3 4,4 5,5 and 6,6.
Other than these two my answers are the same (or differ by +/- 0.1) so I assume they should be right.
Ouch I didn't read carefully. Thanks.
Thanks for the head up. All solutions correct now.
Predict for the percentage to get A1 for this E maths paper for this O level?
Solutions were corrected according to feedback thanks. Made a mistake in question 10 due to rush.