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"A-Level/Higher Maths Help"

I hate to stinge help, but I need it :S

The tangent to the curve y = ax² + 3 ax + 6 at the point where x = 1 makes an angle of 45 degrees with the x axis in positive direction. Calculate the value of a.

I've tried synthetic division, differentiation, equation of straight line, y-1 equals y-2 but had no luck!

Please, help! :)

(I have to go, PC shutdown, so I won't reply till morning)

I hate to stinge help, but I need it :S

The tangent to the curve y = ax² + 3 ax + 6 at the point where x = 1 makes an angle of 45 degrees with the x axis in positive direction. Calculate the value of a.

I've tried synthetic division, differentiation, equation of straight line, y-1 equals y-2 but had no luck!

Please, help! :)

(I have to go, PC shutdown, so I won't reply till morning)

Ah, higher maths, the lessons where almost as soon as my teacher opened his mouth i tuned out and walked in a fantasy land where maths was irrelevent.

Still got a C though, w00t.

Do dy/dx and then substitute x=-1 into your new equation. Now help me with question 5.

phuzzy wrote:
> I hate to stinge help, but I need it :S
>
> The tangent to the curve y = ax² + 3 ax + 6 at the point where x
> = 1 makes an angle of 45 degrees with the x axis in positive
> direction. Calculate the value of a.
>
> I've tried synthetic division, differentiation, equation of straight
> line, y-1 equals y-2 but had no luck!
>
> Please, help! :)
>
> (I have to go, PC shutdown, so I won't reply till morning)

Hmmm thats a toughie, you could do with the y co-ordinate of that point where x=1

Hmm i suppose the gradient at that point is 1. dy/dx of the original equation is 2ax+3a, so that equals the gradient. And at the point x=1. so 5a=1 which would make a=1/5 but i'm not certain that i'm right.

-

If I could remember how to, I'd tell you the answer.

I know it involves differentiationainon and/or integration but that's about it!

Hmmm, looking at it now, i think my answer is right. If you put 1/5 into the equation and differentiate it gives the right answer, that is assuming that the gradient at x=1 is 1!

phuzzy wrote:
> I hate to stinge help, but I need it :S
>
> The tangent to the curve y = ax² + 3 ax + 6 at the point where x
> = 1 makes an angle of 45 degrees with the x axis in positive
> direction. Calculate the value of a.
>
> I've tried synthetic division, differentiation, equation of straight
> line, y-1 equals y-2 but had no luck!
>
> Please, help! :)
>
> (I have to go, PC shutdown, so I won't reply till morning)

now i don't like to brag (carrys on anyway) but i am quite good at maths and i haven't quite got to a-level... but i can get you proffesional advice (my maths teacher won some guiness world record in maths) but hes not here now so i have a crack at it *everybody sighs*...

a = 5x(sqared) 15% sure on this one its just to hard...

don rocco wrote:
> Do dy/dx and then substitute x=-1 into your new equation.