Answer:
[tex]5m^4 n[/tex]
Step-by-step explanation:
By the binomial expansion,
[tex](a+b)^n =\sum_{r=0}^{n} ^nC_r a^{n-r} b^r[/tex]
Using this,
[tex](m+n)^5 =\sum_{r=0}^{5} ^5C_r m^{5-r} n^r[/tex]
For finding 2nd term,
Put r = 1, ( because terms start from 0 to 5 )
Second term = [tex]^5C_1 m^{5-1} n^1[/tex]
[tex]=\frac{5!}{1!4!} m^4 n^1[/tex]
[tex]=5m^4 n[/tex]
