Question

. If x=5-squ. 21/2,

find the value of x+1/xsqu.​

Answer 1

Answer:

Given

x = (5 - v21)/2

1/x = 2/(5 -v21)

=2(5 + v21)/(5 - 21)(5 + 21)

= (5+ v21)/2

hence,

x + 1/x = (5 -v21)/2 + (5+/21)/2 =5

x2 + 1/x = (x + 1/x)2 -2x.1/X

= (x + 1/x)-2

=(5)2-2

= 23