Line 145: |
Line 145: |
| | | |
| = Hints for difficult problems = | | = Hints for difficult problems = |
− | Irrational numbers | + | Irrational numbers<br> |
− | Exercise 1.3.1 | + | Exercise 1.3.1<br> |
| + | |
| 1.Write four possible irrational numbers between 4 and 5. | | 1.Write four possible irrational numbers between 4 and 5. |
| + | |
| Solution: | | Solution: |
| + | |
| Consider the squares of 4 and 5 | | Consider the squares of 4 and 5 |
| | | |
− | 42 = 16 and 52 = 25
| + | Square of 4 = 16 and Square of 5 = 25 |
− | We can also wright 4 and 5 as | + | |
− | =4 and =5 | + | We can also write 4 and 5 as |
| + | |
| + | √ 16 =4 and √ 25 =5 |
| | | |
| Between and there exists | | Between and there exists |
− | ,,,,,,,
| |
| | | |
− | 2.Write four rational numbers between and
| + | √ 17 ,√ 18 , √ 19 , √ 20 , √ 21 , √ 22 , √ 23 , √ 24 |
− | Solution:
| |
− | root 2 ~1.414 and
| |
− | root 3 ~ 1.732
| |
− | Rational numbers of root2 and root 3 is in between 1.4 to 1.7 like 1.45,1.5,1.55, 1.6 ........
| |
− | | |
− | 3.Prove that + is an irrational number
| |
− | Solution:
| |
− | Let us assume on contrary that is a rational number.
| |
− | Then there exists co-prime positive integers p and q such that
| |
− | =
| |
− | -=
| |
− | (-)2 = ()2
| |
− | +2- 2.= 5
| |
− | =
| |
− | p and q are integers
| |
− | is rational
| |
− |
| |
− | But this contradicts the fact that is irrational.
| |
− | So, our assumption is wrong.
| |
− | Hence, is irrational
| |
− | Write an irrational
| |
| | | |
| = Project Ideas = | | = Project Ideas = |