Monday, October 30, 2006

LINEAR EQUATIONS OF TWO VARIABLES-IMPORTANT TIPS

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IMPORTANT TIPS:




  • ax+b = 0 (a,b are real numbers and a is nonzero) is a linear equation of one variable. Thus, 2x+3 = 0 and 0.4x-5 = 0 are linear equations of one variable.

  • ax+by+c = 0(a,b,c are real numbers and a and b are not equal to zero simultaneously)is a linear equation of two variables. Thus, 3x-2y+4 = 0 and(2x/3)+(4y/5)-6 = 0 are linear equations of two variables.

  • y = (-a/b)x-(c/b) or y = (-ax-c)/b is called y-form of the equation ax+by+c = 0

  • If we have only one equation, ax+by+c = 0, then it has got infinite solutions because for each value of x we get some value of y which satisfies the equation.

  • If we have a pair of equations a1x+b1y+c1 = 0 and a2x+b2y+c2 = 0,then there are three possibilities:
    1. The equations have a particular(unique) solution where unique values of x and y satisfy both equations. This happens when a1b2-a2b1≠ 0

    2. The equations do not have a solution, i.e. there is no set of values of both x and y which can satisfy both equations. This happens when a1b2-a2b1 = 0 and either b1c2-b2c1≠ 0 or c1a2-c2a1≠ 0

    3. The pair of equations has infinite solutions.This happens when a1b2-a2b1 = b1c2-b2c1 = c1a2-c2a1 = 0


  • METHOD OF CROSS MULTIPLICATION:

    Let the given pair of equations be:

    a1x+b1y+c1 = 0
    a2x+b2y+c2 = 0

    (a1, b1 and a2, b2 are not zero simultaneously)

    To understand the procedure READ THE DETAILS IN THE FOLLOWING IMAGE and
    To read the details clearly ENLARGE IT by opening it in another window.





    What we have done while going from step (A) to step (B) is :

    Write the product of b1 andc2 (downward arrow) minus the product of b2 and c1 (upward arrow) below x. Follow the same procedure for y and 1.

    So, we get (B). NEXT ?

    x = b1c2 - b2c1
          a1b2 - a2b1

    and

    y = c1a2 - c2a1
          a1b2 - a2b1



    Thus, we get the values of x and y which satisfy the given pair of equations.

  • PRACTICAL PROBLEMS:

    In solving practical problems, one must not forget that it is the lack of proper understanding of the language that makes the solution difficult.So, while solving practical problems with the help of linear equations :
    1. Read the statement carefully.
    2. Analyse it thoroughly.
    3. Form correct equations.


    This requires great patience and exhaustive practice.More you practise, more you understand the method.



DESSERT

2 is the only prime which is even!

Friday, October 27, 2006

INTRODUCTORY NOTE

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It is a general impression among highschool students and their parents that Mathematics is a very tough subject to digest.In fact, about 40% of a student's study time is utilized for mathematics only.It is obvious and essential because mathematics is not a novel or a collection of short stories which you finish in one go. It is a subject which asks for visualization, computing skills,power of analysis and persistence in effort.

MATHEMATICS differs from other subjects in the sense that you cannot afford to forget basic concepts and methods you have studied previously.You can and sometimes you do forget the story of a king and his adventures which you were tought in Class VI or Class VII. You cannot afford to forget Methods of Factorization or Mathematical Identities when you enter Class X.The story of Class VII has no connection to the one you are going to study in Class X, but the topics of mathematics do have basic connections as you move forward. This aspect makes Mathematics an entirely different subject.

REMEMBER:


MATHEMATICS, AS FAR AS I HAVE EXPERIENCED AND ENJOYED, IS NOT A TOUGH SUBJECT AT ALL

WHAT YOU MUST REMEMBER



The following is a list of some important mathematical rules, formulas, methods, etc. ,which you have already studied uptil now and which you cannot afford to forget.Most of the students ignore this very important fact and it is too late when they realise what they missed.You must remember:

  • Tables of 1-20(at least)

  • Squares of 1-25(at least)

  • Cubes of 1-12

  • Decimal Calculations

  • Percentage Calculations

  • Calculation of HCF/GCF and LCM

  • Conversion of Units(e.g. 1 m= 100 cm)

  • All important Mathematical Identities and their Proper Use.

  • All methods of factorization

  • Rules of Indices

  • Rules and Methods connected to Ratio and Proportion

  • All Geometrical Definitions and Concepts(point,ray,line.angle,plane,etc.)

  • Types of Triangles and Quadrilaterals

  • Properties of Triangles and Quadrilaterals

  • Formulas to calculate Perimeter, Area, Volume,etc.

  • Preliminary Trigonometry

  • Preliminary Set Theory and Set Operations.


Once you have mastered these all, your studies will become much easier and more interesting.

A PUZZLE FOR FUN



Harsh went to a departmental store to purchase something.He spent half of the total amount he had when he entered the store.When he came out he had just as many paise as he had rupees while entering the store and half as many rupees as he had paise while entering the store.What amount actually Harsh carried when he entered the store?

WELCOME TO MY MATHS BLOG

Welcome my dear students,
Your MANOJSIR is now available on net to solve your problems of mathematics.I will be posting topics of mathematics of Class 10 of Gujarat Secondary Education Board(GSEB).I hope that this will be of help to every student of Class 10 studying in any EDUCATION BOARD OF INDIA.

This is my humble effort to serve my students.


INDEX-TOPIC SEARCH
*INTRODUCTORY NOTE

*LINEAR EQUATIONS OF TWO VARIABLES-TIPS

*HCF AND LCM OF POLYNOMIALS-TIPS

*RATIONAL EXPRESSION

*QUADRATIC EQUATION-TIPS

*ARITHMETIC PROGRESSION-TIPS

*INSTALMENTS-TIPS

*INCOME TAX-TIPS

*MEAN-TIPS

*SIMILAR TRIANGLES-TIPS

*CONDITIONS FOR SIMILARITY-TIPS

*SIMILARITY AND PYTHAGORAS' THEOREM-TIPS