Question

if x = 5 - 2 root 6 Find the value of x2 + 1/x 2

Answer 1

Answer:

x²+1/x² = 98

Explanation:

i) x = 5-2√6 -----(1)

ii )1/x = 1/(5-2√6)

= (5+2√6)/[(5-2√6)(5+2√6)]

= (5+2√6)/[5²-(2√6)²]

= (5+2√6)/(25-24)

= 5+2√6----(2)

Now ,

iii )x + 1/x

= 5-2√6+5+2√6

= 10 -----(3)

iv ) x² + 1/x²

= (x+1/x)² - 2

= (10)² - 2

= 100 -2

= 98

••••

Answer 2

5=5-2 root 6

then 1/X=5+2 root 6

(5-2 root 6)^2+(5+2 root 6)^2

25+24-20 root 6+25+24+20 root 6

25+24+25+24

50+48

98