Changes
From Karnataka Open Educational Resources
811 bytes added
, 06:19, 23 February 2014
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| = Hints for difficult problems = | | = Hints for difficult problems = |
| + | Irrational numbers |
| + | Exercise 1.3.1 |
| + | 1.Write four possible irrational numbers between 4 and 5. |
| + | Solution: |
| + | Consider the squares of 4 and 5 |
| + | |
| + | 42 = 16 and 52 = 25 |
| + | We can also wright 4 and 5 as |
| + | =4 and =5 |
| + | |
| + | Between and there exists |
| + | ,,,,,,, |
| + | |
| + | 2.Write four rational numbers between and |
| + | 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 |
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| = Project Ideas = | | = Project Ideas = |