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| Image Credits: Tomáš Kebert & umimeto.org (wikimedia) |
Fill in the blanks with suitable words.
1. Soil is formed by the breaking down of rocks, by the action of wind, water and climate, called __________.
2. The removal of land surface by water, wind or ice is known as ________.
3. ________ soil having organic matter and a good capacity to retain water are ideal sources for growing paddy.
Fill in the blanks with suitable word(s).
1. Numbers having more than two factors are called _____________ numbers.
2. A _______ of a number is an exact divisor of that number.
3. ______ is a factor of every number.
Cube root is the inverse operation of a cube.
Symbol ∛ represents a cube-root.
e.g. $\sqrt[3]{8} = 2$,
$\sqrt[3]{216} = 6$
METHODS OF FINDING CUBE ROOT
There are two methods of finding Cube Root
1. Prime Factorisation
2. Estimation Method
Q1: Which of the following statements is wrong for viroids?
(a) They cause infections.
(b) Their RNA is of high molecular weight.
(c) They lack a protein coat.
(d) They are smaller than viruses.
Class 9 Maths - Important Identities
(a+b)² = a² + 2ab+ b²
(a–b)² = a² –2ab + b²
a² – b² = (a+b)(a–b)
Q1: Define nationalism.
Answer: The expression of Nationalism was brought about by the French revolution in 1789. Nationalism developed a sense of common identity and shared past or descent. Political movements and struggles by the leaders led to the current commonness. It emerged as a force to unify people which later led to the emergence of the nation-state.
Q2: Who was Frederic Sorrieu?
Answer: He was a French artist famous for a series of four prints prepared in 1848 that visualised the dream of a world consisting of ‘Democratic and Social Republics’.
RELATION
Let A and B be two nonempty sets. Then, a relation R from A to B is a subset of (A × B).
Thus, R is a relation from A to B ⇔ R ⊆ (A × B).
If (a, b) ∈ R then we say that ‘a is related to b‘ and we write, a R b.
If (a, b) ∉ R then ‘a is not related to b‘ and we write, $a \not \mathrel{R} b$.
Q1: Let A = {-1, 2, 4} and B = {1, 3}. Show A × B as arrow diagram.
