POLYNOMIALS -CHAPTER 2.1 NCERT

                      POLYNOMIALS



                                   
Important definitions
Variable: It changes its values according to the condition given.
As Ram's Age is not known, assume (x) years.
Example-
Rohit's income is not given, so assume x in rupees.
Here, we can see that we have assumed the value x in two different categories 
Constant 
It does not change
As -2, 5, 7, 1000, etc. 

Types of polynomials
Monomial: An expression  containing a single term 
ex - ax^2 
Binomial: An expression containing two variables 
Example : x +y, x^2 +y^2 
Trinomial 
An expression containing three variables is called a trinomial - x +y +z
* An expression containing more than three variables is said to be a polynomial 
We express a polynomial by writing the symbol p(x)

Zeros of a polynomial

The value of a variable that makes the polynomial zero is said zero of the polynomial.
Alternatively, we obtain zero when we substitute the variable's value into the expression, and it yields the answer zero. 
Example: Find the zero of the polynomial 
p(x): x^2 -4
"^" is used to  show the power
If you put x=2 in the p(x), see what you get-

p(2): 2^2 -2 = 4-4 =0 
So, X=2 is the zero of the polynomial p(x).

How to find the zeros from the graph? 

Very simple, in the graph, see how many times the curve or the line crosses or touches the X-axis, which will give you the number of zeros.


ncert exercise 2.1 questions
(Question figure given in the textbook)

(i) In the first graph, you can see line is parallel to the X axis; it does not touch or cut the X axis. So, the number of zeros = 0
(ii) The curve crosses the X-axis one time; therefore, the number of zeros = 1.
(iii) The curve crosses the X axis for three times; hence, the number of zeros is =3
(iv) It is easily seen that the curve crosses the X axis, so the number of zeros = 2.
(v) The curve crosses the x-axis four times. Hence, the number of zeros = 4
(vi) The curve crosses the X axis once and touches it once, hence, the total solution = 2
----End of Chapter 2.1 -----
The next chapter, 2.2, will be available shortly on the other page.


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