For natural number m, n, if (1−y)m(1+y)n=1+a1y+a2y2+..., and a1=a2=10, then
A
m<n
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B
m>n
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
m+n=80
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D
m−n=20
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution
The correct options are Am<n Cm+n=80 (1−y)m(1+y)n=(1−mC1y+mC2y2−...)(1+nC1y+nC2y2+...) =1+(n−m)y+(m(m−1)2+n(n−1)2−mn)y2+... Given, a1=10 ⇒a1=n−m=10⋯(1) ⇒a2=m2+n2−m−n−2mn2=10 ⇒(m−n)2−(m+n)=20 ⇒m+n=80⋯(2) Solving (1) and (2), we get m=35,n=45.