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Quadratics a level maths help!

14656672412511938824410.jpgpls do these two questions for me. Do it on paper n take a photo of the solutions and send them to me. Very urgent!
Reply 1
Original post by Yoora3
14656672412511938824410.jpgpls do these two questions for me. Do it on paper n take a photo of the solutions and send them to me. Very urgent!


Eh, no. What's your problem? What's confusing you? What have you tried?
Reply 2
Have you even tried them? What's the problem?

edit: lol beat me to it ^
Reply 3
I did try. But i don't have the answers. And am weak in quadratics. For the first question i don't know how to sketch. For the second one, i don't understand part (ii)
Reply 4
Original post by Parallex
Have you even tried them? What's the problem?

edit: lol beat me to it ^


I don't know how to do it at all.
Reply 5
Original post by Yoora3
I did try. But i don't have the answers. And am weak in quadratics. For the first question i don't know how to sketch. For the second one, i don't understand part (ii)


If you want us to check your answers, then put your answer up and we'll check it. You don't need to sketch for the first part, you're just meant to interpret geometrically the solutions to those two curves. hint: think about intersections.

The domain of f^(-1)(x) is the range of f(x). f(x) is a quadratic and has a minimum point, see if you can work out the range of that.
Reply 6
Original post by Yoora3
I did try. But i don't have the answers. And am weak in quadratics. For the first question i don't know how to sketch. For the second one, i don't understand part (ii)


To sketch, factorise the quadratic to find the roots then just plot the axis intersections and draw the curve from them. I'm sure you don't have a problem drawing a y=mx+c line.

for 2ii) it'd be a good start to find the range of f(x)f(x). You should know the relationship between f(x)f(x) and f1(x)f^{-1}(x) geometrically -which will help you find the domain of the inverse function.
Have you tried it yourself at least ?

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(edited 7 years ago)
Reply 8
1465668351342170826041.jpg
Original post by Zacken
If you want us to check your answers, then put your answer up and we'll check it. You don't need to sketch for the first part, you're just meant to interpret geometrically the solutions to those two curves. hint: think about intersections.

The domain of f^(-1)(x) is the range of f(x). f(x) is a quadratic and has a minimum point, see if you can work out the range of that.
Reply 9
Original post by Yoora3
1465668351342170826041.jpg


All you have to do for (i) is just show that the discriminant of the quadratic you are left with is smaller than 0.

The completing the square bit looks good, well done!
Original post by Yoora3
1465668351342170826041.jpg


For part (I) I think you should do b^2-4ac and it should be less that 0 to prove that it has no real roots.


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Reply 11
Original post by Zacken
All you have to do for (i) is just show that the discriminant of the quadratic you are left with is smaller than 0.

The completing the square bit looks good, well done!

How about the sketch??
Reply 12
Is the sketch good for question 1?? The solution is (3,2) - - - the answer i got.
Reply 13
Original post by Yoora3
How about the sketch??


I'm not sure what the sketch is for?
Damn, question 3 looks tough!

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