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India Pre-Regional Mathematical Olympiad
2016 India PRMO
7
7
Part of
2016 India PRMO
Problems
(1)
2016 preRMO p7, coefficient of a^5b^5c^5d^6 in (bcd + acd + abd + abc)^7
Source:
8/9/2019
Find the coefficient of
a
5
b
5
c
5
d
6
a^5b^5c^5d^6
a
5
b
5
c
5
d
6
in the expansion of the following expression
(
b
c
d
+
a
c
d
+
a
b
d
+
a
b
c
)
7
(bcd +acd +abd +abc)^7
(
b
c
d
+
a
c
d
+
ab
d
+
ab
c
)
7
combinatorics
coefficient
algebra