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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)

dy/dx = 2ax + 3a
dy/dx = 5a
so, a = 1/5

But someone said x = -1
so dy/dx = a
So, a = 1

don rocco wrote:

> Phuzzy your mistake was using x=1, look at the question sheet again,
> it says x=-1.

Hehe! I always used to fall for that one! :-D

don rocco wrote:
> Phuzzy your mistake was using x=1, look at the question sheet again,
> it says x=-1.

Ah, that would help :D

I thought the hypen looked a lil faint compared to rest of page, so ignored it.

Thanks again :D

Ta all, got it!

You guys rocks :D

christ that is one mean equation. I only doing my GCSE coursework so dun ask me dude.

Well I do Further Maths, (double A-Level) so I should know my stuff... but sadly I dont. Me need to revise I think.

don rocco wrote:
> The answer is 1. Heres how I did it (we were given the answers as
> well, so I know its correct):
>

Gutted. Im obviously rubbish at maths then. Dunno what i did wrong.


Edit:- now that ive looked how to do it, it doesnt seem difficult. i feel so stupid now

Hah, brings back not so fond memories!

The answer is 1. Heres how I did it (we were given the answers as well, so I know its correct):

y=ax2+3ax+6
dy/dx=2ax+3a
dy/dx=2a(-1)+3a
1=-2a+3a
1=a

Phuzzy your mistake was using x=1, look at the question sheet again, it says x=-1.

I recon the answer could be:

a = -5/4

(thats minus five quarters)

Might not be righ tho.

What module of maths is it, and is it AS or A2?