Question

If x^2 + 1/x^2 = 98 find x + 1/x

​

Answer 1

Given,

x
2
+
x
2

1
​
=98

(x+
x
1
​
)
2
=x
2
+
x
2

1
​
+2

98+2=100

∴x+
x
1
​
=10

(x+
x
1
​
)
3
=x
3
+
x
3

1
​
+3(x+
x
1
​
)

x
3
+
x
3

1
​
+3(x+
x
1
​
)=1000

x
3
+
x
3

1
​
=1000−3(10)=