Show that the ratio of the coefficient of x10 in the expansion of (1 – x2)10 and the term independent of x in the expansion of
is 1 : 32.
To Prove : coefficient of x10 in (1-x2)10: coefficient of x0 in
= 1:32
For (1-x2)10 ,
Here, a=1, b=-x2 and n=15
We have formula,
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To get coefficient of x10 we must have,
(x)2r = x10
• 2r = 10
• r = 5
Therefore, coefficient of x10![]()
For
,
Here, a=x,
and n=10
We have a formula,
![]()
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Now, to get coefficient of term independent of xthat is coefficient of x0 we must have,
(x)10-2r = x0
• 10 - 2r = 0
• 2r = 10
• r = 5
Therefore, coefficient of x0![]()
Therefore,

![]()
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Hence,
coefficient of x10 in (1-x2)10: coefficient of x0 in
= 1:32