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Maths Q7 c (1 Viewer)
- Thread starter donrob15
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earthnfire
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donrob15 said:
I'm pretty sure my answer is right. I wrote:
ab = c/a = 1
as: ab=1
b= 1/a
Therefore a + 1/a is the same as a + b = 3
So a + 1/a = 3
Hope this helps...goodluck with the rest of your exams.
Last edited:
chainedchaos
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Where y=2x^2 +kx + 9 does NOT intersect with y=2x + 1:
2x^2 +kx + 9 (is not equal to sign) 2x +1
then you just rearrange it to get 2x^2 +(k-2)x + 8 which is now not equal to zero. So you put the discriminant(from i) < 0 because there are no real roots.
Then you cansolve the inquality like any other quadratic inequality
2x^2 +kx + 9 (is not equal to sign) 2x +1
then you just rearrange it to get 2x^2 +(k-2)x + 8 which is now not equal to zero. So you put the discriminant(from i) < 0 because there are no real roots.
Then you cansolve the inquality like any other quadratic inequality
earthnfire
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Lol...soz...i just realised i answered the wrong question...i answered 7a. I can't help you with 7c...i had the same trouble as you...lol
but goodluck with ur other exams anyway
but goodluck with ur other exams anyway
shinji
Is in A State Of Trance
oh, this is easy. lol
just wats it me called ..... solve them simulataneously
and then u should get a similar equation to the one in part II or sumin
and then u use the discriminate equation from part I or watever
and then u just make it less than 0 ~~
just wats it me called ..... solve them simulataneously
and then u should get a similar equation to the one in part II or sumin
and then u use the discriminate equation from part I or watever
and then u just make it less than 0 ~~
i figured it out 
you let the straight line = the parabola in part 2. you make it all = 0 and you end up getting the discriminant you found in part i. the discriminant has to be <0 for it to not intersect the st line. solve x for discriminant<0. i got -6<k<10. i only wish i knew that in the test.
you let the straight line = the parabola in part 2. you make it all = 0 and you end up getting the discriminant you found in part i. the discriminant has to be <0 for it to not intersect the st line. solve x for discriminant<0. i got -6<k<10. i only wish i knew that in the test.
Yeah i got the two K values but i didn't know the equation had already gotten the curves/ lines merged together.
There i skipped it and didn't bother completing and just had the stupid k values. I knew it was going to be an inequality but i thought i had to rewrite the equation for the two lines to be solved, but it was already fcuking rewritten. BOS could have said that. Bastards
There i skipped it and didn't bother completing and just had the stupid k values. I knew it was going to be an inequality but i thought i had to rewrite the equation for the two lines to be solved, but it was already fcuking rewritten. BOS could have said that. Bastards
