Aptitude - Square Root and Cube Root - Discussion
Discussion Forum : Square Root and Cube Root - General Questions (Q.No. 7)
7.
| If x = | 3 + 1 | and y = | 3 - 1 | , then the value of (x2 + y2) is: |
| 3 - 1 | 3 + 1 |
Answer: Option
Explanation:
| x = | (3 + 1) | x | (3 + 1) | = | (3 + 1)2 | = | 3 + 1 + 23 | = 2 + 3. |
| (3 - 1) | (3 + 1) | (3 - 1) | 2 |
| y = | (3 - 1) | x | (3 - 1) | = | (3 - 1)2 | = | 3 + 1 - 23 | = 2 - 3. |
| (3 + 1) | (3 - 1) | (3 - 1) | 2 |
x2 + y2 = (2 + 3)2 + (2 - 3)2
= 2(4 + 3)
= 14
Discussion:
45 comments Page 1 of 5.
Nithin said:
1 decade ago
(a+b)2 + (a-b)2 = 2(a2 + b2)
Gaurav said:
1 decade ago
Asnwer to this seems to be '-10'.
Tank Mayur B. said:
1 decade ago
This is wrong solution .
because: ((a+b)/(a-b))*((a+b)/(a+b))=(a+b)2/(a2 + b2)
because: ((a+b)/(a-b))*((a+b)/(a+b))=(a+b)2/(a2 + b2)
M.V.KRISHNA/PALVONCHA said:
1 decade ago
Hello gaurav and tank mayur.
This is the process of rationalization.
The denominator is multiplied and divided to selected value.
Hope you understand.
This is the process of rationalization.
The denominator is multiplied and divided to selected value.
Hope you understand.
Mayur said:
1 decade ago
Hello M.V.Krishna
You are absolutely right
Thank you....
You are absolutely right
Thank you....
Yogendra said:
1 decade ago
This can also be solvein this formula: (A+B)2 =(a+b)2-2ab
Raje said:
1 decade ago
Its called conjugate . + in denominoter means u have to multiply & divide the same number but put - sign. denominoter - sign means put + vice versa.
Shyam said:
1 decade ago
Rationalizing the denominator. Makes it very easy and find xy.
Anjani said:
1 decade ago
We can do help from the equation (x2+y2)=(x+y)2-2xy;
Priya said:
1 decade ago
How did we get 2(4+3) ???
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