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State whether the following statements are true or false. Give reasons for your answers.
(i) Every natural number is a whole number.
(ii) Every integer is a whole number.
(iii) Every rational number is a whole number.
(i) True, since the collection of whole numbers contains all natural numbers.
(ii) False, for example, - 2 is an integer but not a whole number.
(iii) False, for example, is a rational number but not a whole number.
Insert three rational numbers between
Are the following statements true or false? Give reasons for your answers.
(i) Every whole number is a natural number.
(ii) Every integer is a rational number.
(iii) Every rational number is an integer.
(i) False, because zero is a whole number but not a natural number.
(ii) True, because every integer m can be expressed in the form and so it is a rational number.
(iii) False, because is a rational number but not an integer.
State whether the following statements are true or false. Justify your answers.
(i) Every irrational number is a real number.
(ii) Every point on the number line is of the form where m is a natural number.
(iii) Every real number is an irrational number.
(i) True, since collection of real numbers is made up of rational and irrational numbers.
(ii) False, because no negative number can be the square root of any natural number.
(iii) False, for example, 2 is real but not irrational.
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Real
,Rational Number
,Irrational Number
Yes! We can predict the decimal expansions of without actually doing the long division as follows:
To predict the decimal expansion of locate when the remainder becomes 2 and respective quotient (here it is 2). Then write the new quotient beginning from there using the repeating digits 1, 4, 2, 8, 5, 7.
Let
Multiplying both sides by 10 (since one digit is repeating), we get
10x = 6.666 ....... 10x = 6 + 0.6666 .....
10x = 6 + x
10x - x = 6
9x = 6
Thus,
Here p = 2
q = 3 ()
Let x = = 0.47777 ......
Multiplying both sides by 10 (since one digit is repeating), we get
10x = 4.7777 ...... 10x = 4.3 + 0.47777 .......
10x = 4.3 + x
10x - x = 4.3
9x = 4.3
Here, p = 43
q = 90 ()
Let x =
Multiplying both sides by 1000 (since three digits are repeating), we get
1000x = 1.001001 ....... 1000x = 1 + 0.001001001 ........
1000x = 1 + x
1000x - x = 1
999x = 1
Thus.
Here, p = 1
q = 999
Let x = 0.99999......
Multiplying both sides by 10 (since one digit is repeating), we get
10x = 9.9999 ......... 10x = 9 + 0.99999 ......
10x = 9 + x
10x - x = 9
9x = 9
Thus, 0.99999 ....... = 1 =
Here, p = 1
q = 1
Since 0.99999......goes on for ever, so there is no gap between 1 and 0.99999......and hence they are equal.
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0.01001 0001 00001.......,
0.20 2002 20002 200002.......,
0.003000300003......,
Three different irrational numbers between the rational numbers and
can be taken as
0.75 075007500075000075......
0.7670767000767.......
0.808008000800008.......
0.3796
∵ The decimal expansion is terminating.
∴ 0.3796 is a rational number.
∵ The decimal expansion is non-terminating recurring.
∴ 7.478478......is a rational number.
1.101001000100001......
∵ The decimal expansion is non-terminating non-recurring.
∴ 1.101001000100001...... is an irrational number.
The two irrational numbers between 0.1 and 0.12 can be taken as
0.1010010001......
and 0.11010010001.....
First Method
The two irrational numbers between 2 and 2.5 can be taken as
2.101001000100001......
and 2.201001000100001.......
Second Method
Note: If a and b are two distinct positive rational numbers such that ab is not a perfect square of a rational number, then is an irrational number lying between a and b.
∴ An irrational number between 2 and 2.5
Similarly, an irrational number between 2 and
∴ Two irrational numbers between 2 and 2.5 are and
Give two rational numbers lying between
0.232 332 333 2 3333 2...... and 0.212 112 111 2 1111......
Two rational numbers lying between
0.232 332 333 2 3333 2......
and 0.212 112 111 2 1111......
can be taken as 2.221 and 2.222.
⇒ x = 5.3474747......
⇒ 10x = 53.474747...... ...(1)
⇒ 1000x = 5347.474747...... ...(2)
Subtracting (1) from (2), we get
990x = 5294
Express in the form of
where p and q are integers and q ≠ 0.
Let
Then, x = 0.001 001 001 001...... ...(1)
⇒ 1000x = 1.001 001 001 001...... ...(2)
Subtracting (1) from (2), we get
99x = 1
Infinitely many irrational numbers lie between and
One irrational number between and
is
Another irrational number between and
is
Third irrational number between and
is
One irrational number is
Another irrational number is
Solution not provided.
Ans. 3.3333...... = 0.875; 0.142857 142857 .......
Solution not provided.
Solution not provided.
Ans.
Solution not provided.
Ans.
Solution not provided.
Ans.
Solution not provided.
Ans.
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x2 = 5
x2 = 5
Then,
Now, let us treat the line BC as the number line, with B as zero, C as 1, and so on. Draw an arc with centre B and radius BD, which intersects the number line in E.
Then, E represents
Now, let us treat the line BC as the number line, with B as zero, C as 1, and so on. Draw an arc with centre B and radius BD, which intersects the number line in E.
Then, E represents
Sollution not provided.
All are irrational numbers.
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5p - 3 × 32p - 8 = 225
⇒ 5p - 3 × 32p - 8 = 52 × 32
⇒ p – 3 = 2
2p - 8 = 2
⇒ p = 5
0.01001 0001 00001.......,
0.20 2002 20002 200002.......,
0.003000300003......,
a = 0 and b =
Then, ab = 0 x which is rational.
Hence, 'ab' is not necessarily an irrational.
5p - 3 × 32p - 8 = 225
⇒ 5p - 3 × 32p - 8 = 52 × 32
⇒ p – 3 = 2
2p - 8 = 2
⇒ p = 5
If a = 2, b = 3, then find the values of the following:
(i) (ab + ba)-1 (ii) (aa + bb)-1
(i) (ab+ba)-1
= (23 + 32)-1
= (8 + 9)-1
= (17)-1
=
(ii) (aa + bb)
= (22 + 33)-1
= (4 + 27)-1
= (31)-1
Show that
(xa - b)a + b. (xb - c)b + c. (xc - a)c + a = 1
(xa - b)a + b. (xb - c)b + c. (xc - a)c + a
= x(a - b) (a + b). x(b - c) (b + c). x(c - a) (c + a)
= xa2 - b2. xb2 - c2. xc2 - a2
= xa2 - b2 b2 + b2 - c2 + c2 - a2
= X0
= 1
Solution not provided.
Ans. 1
D.
0.85 385 3853 ......a whole number
C.
an irrational numberC.
non-terminating and non-repeating0.14
0.401 4001 4 00014......
D.
0.401 4001 4 00014......
0.15
0.501 5001 50001 ......
D.
0.501 5001 50001 ......
D.
non-terminating non-recurringB.
positive and rationalC.
positive and rational0.75
0.750 7500 75000 .......
0.7512
C.
0.750 7500 75000 .......
C.
a real numberC.
a rational number3.763
3.1011 0011 0001 .......
D.
3.1011 0011 0001 .......
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