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#1 2007-09-04 02:07:45

Identity
Member
Registered: 2007-04-18
Posts: 934

Miscellaneous Math Marathon

How about a marathon dedicated to any and all non-calculus topics?

Rules:
1. Calculus (limits, derivatives, integration), as well as other absurdly advanced topics (differential geometry, topology etc.) is forbidden. If that's your style you'll have to find another way.
2. Provide working for your solution
3. Post your own problem right after you have solved the previous one.

I'll get started,


Find all roots of x:

Last edited by Identity (2007-09-04 02:09:49)

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#2 2007-09-30 02:30:37

ganesh
Moderator
Registered: 2005-06-28
Posts: 13,154

Re: Miscellaneous Math Marathon

Let x²-9x=y.
The equation becomes y²-7y+12=0
y=[7± √ (49-48)]/2= (7+1)/2or (7-1)/2=4 or 3.
Putting y=4,
x²-9x=4 or x²-9x-4=0.
x=[9± √(81+16)]/2= (9+  √97)/2 or (9- √97)/2.

Putting y=3,
x²-9x=3or x²-9x-3=0.
x=[9± √(81+12)]/2= (9+√93)/2 or (9-√93)/2.


Character is who you are when no one is looking.

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