Question

(x+1/x) ^5 expand using binomial theorem​

Answer 1

(r+1)th term in the expansion of (1−x)

5

is,

T

r+1

=

5

C

r

(1)

r

(−x)

(5−r)

=

5

C

r

(−1)

(5−r)

(x)

5−r

For coefficient of x

5

,5−r=5⇒r=0

Hence coefficient of x

5

is, =

5

C

5

(−1)

5−5

=−1