Aptitude - Surds and Indices - Discussion
Discussion Forum : Surds and Indices - General Questions (Q.No. 15)
15.
| If x = 3 + 22, then the value of |  |
x | - | 1 |  |
is: |
| x |
Answer: Option
Explanation:
|
x | - | 1 | |
2 | = x + | 1 | - 2 |
| x | x |
| = (3 + 22) + | 1 | - 2 |
| (3 + 22) |
| = (3 + 22) + | 1 | x | (3 - 22) | - 2 |
| (3 + 22) | (3 - 22) |
= (3 + 22) + (3 - 22) - 2
= 4.
 |
|
x | - | 1 | |
= 2. |
| x |
Discussion:
48 comments Page 5 of 5.
Surendran said:
5 years ago
Agree, It's (a-b) ^2 formula.
(1)
Shaya said:
4 years ago
For what reason we are multiplying 3-2 √x / 3-2 √x? Please explain me.
Sourabh said:
3 years ago
@All.
If any root number is in the denominator so we have to a rationalization for solving that (means to remove the root number from the denominator) then in this condition we do multiply of denominator number by doing a sign change (in both nominator and denominator).
If any root number is in the denominator so we have to a rationalization for solving that (means to remove the root number from the denominator) then in this condition we do multiply of denominator number by doing a sign change (in both nominator and denominator).
(2)
Obentulu said:
3 years ago
From the first step, how 2 come? Someone explain this better.
(1)
Rishu Raj said:
3 years ago
@All.
Here, basically the value of X = 3+2✓2. Is a square of (✓2+1) ^2.
Here, basically the value of X = 3+2✓2. Is a square of (✓2+1) ^2.
(3)
Deepa said:
3 years ago
Please explain the 4th step.
(2)
Samarth said:
2 years ago
To explain 4th Step we are trying to remove the denominator, it's basically the formula (a+b) * (a-b) = a^2 - b^2.
If we solve a^2 - b^2, in this case, it comes to 9-8 = 1 and thus the denominator becomes 1.
If we solve a^2 - b^2, in this case, it comes to 9-8 = 1 and thus the denominator becomes 1.
(2)
PADUSHA KHAN SHAIK said:
1 year ago
Here we observe that initially, we take (√x+1/√x)=p.
Assume 'p'.
Now s.b.s.
(√x+1/√x)^2 = p^2.
Now step 4.
3 + 2√2 + 3 - 2√2 - 2 = p^2.
6-2 = p^2.
4 = p^2.
P = 2.
Assume 'p'.
Now s.b.s.
(√x+1/√x)^2 = p^2.
Now step 4.
3 + 2√2 + 3 - 2√2 - 2 = p^2.
6-2 = p^2.
4 = p^2.
P = 2.
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