Tuesday, January 4, 2011

Chapter 1.2 Solving Non linear Equations


Solving Non linear Equations

Example1

2y-3x=1  ------ (1)
y+9x2=8 ------ (2)

from (1)       y=(4x+1)/2 ----(3)
                  
sub(1) into (3): (4x+1)/2 + 9x2   - 8 =0

x 2                 3x+1+18x2 -16=0
                     18x2-15+3x=0
                      (18x-15)(x+1)=0

                      18x-15=0 or      x+1=0
                      18x=15               x=-1
                       x=15/18


find y

Example 2


                   3x/y-2y/x=1 --------- (1)
                   5x-3y=12     --------- (2)

(2):              x=(12+3y)/5 ----------(3)

multiply (1) by xy

                   3x-2y2=xy ------------(4)

sub (3) into (4)

                   3(12+3y) 2/5 -2y2=y(12+3y)/5

multiply by 25
                                3(12+3y) 2 -50 y2=5y(12+3y)
                   3(144+72y+9y2)-50 y2=60y+15y2
432+216y+27y2 -50y2 -60y-15y2 =0

                   -38y2-60y+432=0
                   19y2 +30y-216=0
                   (19y+36)(y-6)=0
                   y=-36/19 or y=6

find x


                  
<Equations> tags

Tuesday, December 14, 2010

Maths For A Day

Why is mathematics so important ?

Because it helps us to play board games, monopoly

Calculate how much to pay for your favourite food

Probability of certain outcomes

Creation of new inventions

Let me know more ?

If anyone have any comments :)


Friday, December 10, 2010

Inequality

Jane has 3 pencils . Tom has 10 pencils.
Gary has more pencils than Jane but less than Tom.
How many pencils does Gary have ?

Thursday, December 9, 2010

Tuesday, December 7, 2010

How to change an unknown 2 digit number to algebra ?

34 =  10 x 3 +  1 x 4

How to change an unknown 2 digit number to algebra ?

let the number in the tens place be x
10 x x = 10x

let the number in the tens place be y
1 x y = y

Thus the value of the unknown 2 digit number is 10x + y


Question


Give me algebra of a unknown 3 digit number !




Monday, December 6, 2010

P6 question

There are twice as many sweets than pencils . If each of the girl recieved 1/6 of the mixed amount and each of the boy recieved 1/9 of the mixed amount how many boys and girls are there ?