Quadratic Equations :

Blazing goIITian

Posted on
10 Apr 2009 13:37:01 IST

Posts: 329

10 Apr 2009 13:37:01 IST

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Quadratic Equations :

Mathematics , Algebra

Here are some useful things about this deceptively simple looking chapter :

If ax^2 + bx + c = 0 ... has roots = j,k . . . then :
----------> aj +b = -c/j & ak + b = -c/k

If ax^5 + bx^4 + cx^3 + dx^2 + ex + f = 0 ...Then :

-----------> Sum of all 5 roots = -b/a
-----------> Sum of 5 roots in pair of two = c/a

-----------> Sum of 5 roots in pairs of three = -d/a

-----------> Sum of roots in pair of four = e/a

-----------> Total product of 5 roots = -f/a

If f(x) has n real roots, then f ' (x) has (n-1) real roots.

If a^2 + b^2 + c^2 - ab - bc - ac = 0

then a=b=c

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