If x4+ x-4= 1442, (x > 0) then the value of x - x-1is:
Show answer & explanation
Correct answer: B
Explanation
Correct Answer is option 2 i.e. 6
|
Concept |
Understanding |
Application |
Fair calculation |
|
If (a4 + 1/a4) = x (a2 + 1/a2) = √(x + 2) And If (a2 + 1/a2) = y (a – 1/a) = √(x – 2) |
Given (x4 + 1/x4) = 1442 |
(x4 + 1/x4) = 1442 Applying the formula: (x2 + 1/x2) = √(1442 + 2) = 38 Again, applying the formula: (x – 1/x) = √(38 – 2) = 6 |
√(1444) = 38 √(36) = 6 |