x + 1/x=√2 হলে, x4 +1/x4 =কত?
সমাধান
সঠিক উত্তর: Option A
দেওয়া আছে,
x+ 1/x = √2
x+ 1/x = √2
প্রদত্ত রাশি,
x4+1/x4= (x2)2+(1/x2)2
x4+1/x4= (x2)2+(1/x2)2
= {x2+(1/x)2}2 - 2.x2 .1/x2
= {(x+1/x)2- 2.x.1/x}2-2
= {(√2)2- 2} - 2
= (2 - 2) - 2
= 0 - 2
= -2
= {(x+1/x)2- 2.x.1/x}2-2
= {(√2)2- 2} - 2
= (2 - 2) - 2
= 0 - 2
= -2
