Quantitative Aptitude Ques 1895
Question: If $ x=p+\frac{1}{p} $ and $ y=p-\frac{1}{p}, $ then value of $ x^{4}-2x^{2}y^{2}+y^{4} $ is
Options:
A) 24
B) 4
C) 16
D) 8
Show Answer
Answer:
Correct Answer: C
Solution:
- Given, $ x=p+\frac{1}{p} $ and $ y=p-\frac{1}{p} $
$ x^{2}-2x^{2}y^{2}+y^{4}={{[(x^{2}-y^{2})]}^{2}} $
$ ={{[(x+y)(x-y)]}^{2}} $
$ ={{[ ( p+\frac{1}{p}+p-\frac{1}{p} )( p+\frac{1}{p}-p+\frac{1}{p} ) ]}^{2}} $
[putting the value of a and y]
$ ={{[ (2p)( \frac{2}{p} ) ]}^{2}}=4p^{2}\times \frac{4}{p^{2}}=4\times 4=16 $