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 1 of 5.
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.
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)
Deepa said:
3 years ago
Please explain the 4th step.
(2)
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)
Obentulu said:
3 years ago
From the first step, how 2 come? Someone explain this better.
(1)
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)
Shaya said:
4 years ago
For what reason we are multiplying 3-2 √x / 3-2 √x? Please explain me.
Surendran said:
5 years ago
Agree, It's (a-b) ^2 formula.
(1)
Rakshith said:
6 years ago
@Abisheak.
We have taken that power to get the equation and rooted in the final to get the answer.
We have taken that power to get the equation and rooted in the final to get the answer.
(1)
Abisheak said:
6 years ago
Where is the power 2 comes from in the starting stage? We can See that there is no power mentioned in the question.
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