If rth term in the expansion of (x/3-2/x2)10 contains x4, then find the value of r - Maths - Binomial Theorem

Question

If rth term in the expansion of
(x/3-2/x2)10 contains x4, then
find the value of r

Ishwarmani · Accepted Answer

Dear
Student,
Please find
below the solution to the asked query:

The general term in the expression x3-2x210 is given byTr+1=Cr10x3r-2x210-r=Cr10xr3r-210-rx210-r=Cr10-210-r3rxrx210-r=Cr10-210-r3rxr-210-r=Cr10-210-rx3r-203rAs, rth term contains x4
So, 3r-20=4⇒3r=24⇒r=243∴ r=8

Hope
this
information will clear
your doubts about the
topic
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