>

Published on December 19th, 2010 In category Education | Maths

Search Similar Topic: , , ;

# Algebra cheat sheet- Some important formulas

Consider the quadratic equation ax2 + bx + c .  Suppose that its roots are denoted α and β.

It is possible to show that

• the sum of the roots is α + β =  – ( b/a)
• the product of the roots is α β is = c/a
• For example the equation given is 3x2 -5x +c = 0 then  α + β is  3/5 and α β is  – 1

______________________________________________________________________________

Consider the quadratic equation ax3 + bx2 + cx + d .  Suppose that its roots are denoted α , β and γ.

It is possible to show that

• the sum of the roots is α + β  + γ  =  – ( b/a)
• the product of the roots is α β  + βγ + αγ  is = c/a
• the product of the roots is  α βγ =  – (d/a)
• _____________________________________________________________________________

If an equation (i.e. f(x) = 0) contains all positive co-efficients of any powers of x, it has no positive roots. Eg: x3+5x2+3x+9=0 has no positive roots as all the co-efficients of any powers of x are positive numbers

_____________________________________________________________________________

For a bi-quadratic equation ax4+bx3+cx2+dx+e = 0 , Suppose that its roots are denoted α , β, γ and Φ.

It is possible to show that

• the sum of the roots is α + β  + γ   + Φ  =  – ( b/a)
• Sum of the product of the roots taken three at a timeis as  , αβγ  + βγΦ + αβΦ + αγΦ  is = c /
• Sum of the product of the roots taken two at a time = -d/a
• the product of the roots is  α βγΦ  =  – (d/a)
• If you liked my contribution, please donate or click on any of advt. a little that will be generated will all be donated for noble cause. [paypal-donation] [ad#Textads-BetPost]