x4+2x2+1=5x2 হলে x+1/x=কত?
সমাধান
সঠিক উত্তর: Option D
x4+2x2+1=5x2
or,x4+1=3x2
or,x2(x2+1/x2)=3x2
or,x2+1/x2=3
or,(x+1/x)2 - 2.x.1/x=3
or,(x+1/x)2=3+2=5
∴ x+1/x=√5
or,x4+1=3x2
or,x2(x2+1/x2)=3x2
or,x2+1/x2=3
or,(x+1/x)2 - 2.x.1/x=3
or,(x+1/x)2=3+2=5
∴ x+1/x=√5
