9th Class

  Algebra and Co-ordinate Geometry   In this chapter, we will learn about polynomials, linear equations in two variables and co-ordinate geometry.   Polynomials Polynomials are those algebraic expressions in which the variables involved have only non-negative integral powers. In other words, a polynomial p(x) in one variable x is an algebraic expression in x of the form,        \[P(x)={{a}_{n}}{{x}^{n}}+{{a}_{n-1}}{{x}^{n-1}}+......+{{a}_{3}}{{x}^{3}}+{{a}_{2}}{{x}^{2}}+{{a}_{1}}x+{{a}_{0}}.\] Where \[{{a}_{n}}\],\[{{a}_{n-1}}\],…..\[{{a}_{3}},{{a}_{2}},{{a}_{1}},{{a}_{0}}\]are \[{{a}_{n}}\]\[\ne \]0. Here, \[{{a}_{n}}\],\[{{a}_{n-1}}\],….,\[{{a}_{3}},{{a}_{2}},{{a}_{1}},{{a}_{0}}\] are respectively the coefficients of \[{{x}^{n}},{{x}^{n-1}}\],….,\[{{x}^{3}},{{x}^{2}},x,{{x}^{0}}\] and n is called the degree of the polynomial. Each of \[{{a}_{n}}{{x}^{n}},{{a}_{n-1}},{{x}^{n-1}}\],…..,\[{{a}_{3}}{{x}^{3}},{{a}_{2}}{{x}^{2}},ax,{{a}_{0}}\],is called a term of the polynomial p(x). The degree of the polynomial in one variable is the highest index of the variable in that polynomial.   Note: (i) A non zero constant polynomial is a polynomial of degree 0. For example \[-3,\frac{2}{3,}\sqrt{5}\] etc are constant polynomials. (ii) Constant polynomial 0 is called the zero polynomial. In such a polynomial all the constants more...

  Geometry   In this chapter, we will learn about introduction to euclid’s geometry, lines and angles, triangles, quadrilaterals, areas of parallelograms and triangles and circles.   Axioms Axioms or postulates are the assumptions which are obvious universal truths. They are not proved.   Theorems Theorems are statements which are proved using definitions, axioms, previously proved statements and deductive reasoning.   Euclid’s Axioms
  • The things which are equal to the same thing are equal to one another.
  • If equals be added to the equals, the wholes are equal.
  • If equals be subtracted from equals, the remainders are equals.
  • Things which coincide with one another are equal to one another.
  • The whole is greater than the part.
  • Things which are double of the same thing are equal to one another.
  • Things which are halves of the same thing are equal to one another.
  •   Euclid’s Postulates
  • A more...

  •   Surface Area and Volume   In this chapter, we will learn about some important formulas related to \[2-D\] and \[3-D\] geometrical shapes.   Area of a Triangle
    • Area of a triangle \[=\frac{1}{2}\times \] (Perpendicular) \[\times \] Base
    • Area of a triangle having lengths of the sides a, b and c is
    \[=\sqrt{s(s-a)(s-b)(s-c)}\] sq. units, Where \[s=\frac{1}{2}\] (a + b + c)  
    • Area of an equilateral triangle \[=\frac{\sqrt{3}}{4}{{a}^{2}}\], where a is the side of the equilateral triangle.
      Circle
    • Circumference of the circle = \[2\pi r\]
    • Area of the circle = \[\pi {{r}^{2}}\]
    • Area of the semicircle = \[\frac{1}{2}\pi {{r}^{2}}\]
    • Perimeter of the semicircle =\[\pi r+2r\]
              Length of Arc and Area of a Sector more...

      Statistics and Probability   In this chapter we will learn about statistics and probability.   Statistics Statistics is the branch of Mathematics which deals with data collected for specific purpose.   Central Tendencies of Data The central tendency gives us an idea that represents the entire data. There are three types of central tendencies which are:
    • Mean
    • Median
    • Mode
      Mean It is also known as arithmetic mean of the given observations and is equal to ratio of sum of all the observations and total number of observations, i.e, Mean = \[\frac{Sum\text{ }of\text{ }all\text{ }the\text{ }observations}{Total\text{ }number\text{ }of\text{ }observations}\] \[If\,\,{{x}_{1}},\,\,{{x}_{2}}\], ----\[{{x}_{n}}\]are n observations then its mean   is
  • M. =\[\overline{x}=\frac{{{x}_{1}}+{{x}_{2}}+.....+{{x}_{n}}}{n}\]=\[\frac{\sum{{{x}_{i}}}}{n}\]
  •   Arithmetic Mean for Frequency Distribution Let \[{{f}_{1}},{{f}_{2}}\], ….\[{{f}_{n}}\] be corresponding frequencies of \[{{x}_{1}},{{x}_{2}},{{x}_{3}}\]……..\[{{x}_{n}}\] then
  • M. = \[\frac{{{x}_{1}}{{f}_{1}}+{{x}_{2}}{{f}_{2}}+......{{x}_{n}}{{f}_{n}}}{{{f}_{1}}+{{f}_{2}}+......{{f}_{n}}}=\]\[\frac{\sum\limits_{i=1}^{n}{{{x}_{i}}{{f}_{i}}}}{\sum\limits_{i=1}^{n}{{{f}_{i}}}}\]
  •   Arithmetic Mean for Grouped Data For classified data, we take the class more...

      The Process of Community Planning for Disaster   IMPORTANT TERMS AND CONCEPTS            
  • Community Planning: A forward planning process which identifies human and material resources and puts in place potential response system.
  • Contingency Planning Exercise: A forum and opportunity for all sections of the society to participate in the contribution to the planning process.
  • Village Disaster Management Committee: Formed in each village, it is responsible for initiating disaster preparedness activities.
  • Resource Mapping: It focuses on the locally available resources and assets that can be utilised for building the capabilities of the community during and after disasters.
  • Mock drills: A series of actions usually tried out as a dummy exercise according to a-set plan.
  • BDO: more...

  •   IMPORTANT TERMS AND CONCEPTS  
  • Census.  The official counting of the population, etc., taken after every 10 years.
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  • Demography.  Scientific study of population characteristics.
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  • Average density of population. Number of persons per square km.
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  • Quality of people. It means their economic efficiency, the level of their scientific and technological development, cultural values and socio-political organisations.
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  • Birth rate. Number of births in a year per thousand of population.
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  • Death rate. Number of deaths in a year per thousand of population.
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  • Growth rate. Birth rate minus death rate. It is expressed in percentage. It is the per cent increase in population of a country annually:
  • Birth rate           :           42 per 1000 = 4.2% Death rate          :           18 per 1000 = 1.8% Growth rate        more...

    DEMOCRACY IN THE CONTEMPORARY                1776   :           The American War of Independence broke out.             1789   :           Outbreak of the French Revolution.             1957   :           Ghana became independent.             1973    :          A military coup led by General Augusto Pinochet overthrew Salvador Allende's government in Chile.             1990   :           (a) Elections were held in Myanmar.                                         (b) Lech Walesa became the first popularly elected President of Poland which now became a democracy.             1991   :           (a) In August, a coup occurred in Soviet Union.                                         (b) In December, the Soviet President Gorbachev resigned and a Commonwealth of Independent States consisting of 12 republics was   formed.                                         (c) Aung San Suu Kyi of Myanmar was awarded the Nobel Peace Prize.

    DEMOCRACY IN THE CONTEMPORARY   IMPORTANT PERSONALITIES  
  • Salvador Allende. One of the founders of the Chilean Socialist Party. He was elected President of Chile in 1970. On coming to power, he introduced radical land reforms and was ultimately overthrown by General Pinochet.
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  • General Augusto Pinochet. On 11th September 1973, General Pinochet overthrew Salvador Allende's government and established a dictatorship.
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  • Lech Walesa. Founder of Solidarity, a trade union movement which ended communist rule in Poland. He became President of Poland in 1980.
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  • Kwame Nkrumah. He set up the Convention People's Party in 1949. He led the freedom struggle in Ghana, was its first President and held office till 1966 when he was overthrown by a military coup.
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  • Jawaharlal Nehru. A more...

  • DEMOCRACY IN THE CONTEMPORARY          IMPORTANT TERMS AND CONCEPTS  
  • Democracy.  A form of government which is chosen by the people to work for their welfare and can be voted out by them.
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  • Dictatorship.  It is a form of government in which a person or a group of persons possess absolute power without effective constitutional limitations.
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  • Solidarity.  A trade union movement founded by Lech Walesa which helped to end communist rule in Poland.
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  • Decolonisation.  The process of transfer of power from the colonial powers to independent national governments in Asia and Africa.
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  • United Nations Organisation. An organisation founded in 1945 that includes most countries in the world and serves as an international forum to settle international disputes.
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  • Veto.  more...

  • CONSTITUTIONAL DESIGN   IMPORTANT PERSONALITIES    
  • Nelson Mandela. One of the greatest leaders of the African National movement. He spent 27 years of his life in prison for his opposition to apartheid. He was released in 1990. In 1994, he was elected President of South Africa. He was the first black President of South Africa.
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  • Jhaverbhai Vallabhai Patel. A popular leader of the Indian National Movement. He organised a Satyagraha at Bardoli in 1928. He was the Minister of Home, information and broadcasting in the Interim Government. He is known as the Iron Man of India because of his role in the integration of princely states with the Indian Union.
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  • Abul Kalam Azad. An educationist, author, theologian and Arabic scholar, he was an active participant more...


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