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in Binomial Theorem by (44.0k points)
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In the following expansion, find the indicated coefficients.

x8 in (2x5 - 5/x3)8

1 Answer

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by (44.1k points)
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Best answer

Here, a = 2x5, b = -5/x3, n = 8

We have tr+1 = nCr an-rbr

To get the coefficient of x8, we must have

x40-8r = x8

\(\therefore\) 40 - 8r = 8

\(\therefore\) 8r = 32

\(\therefore\) r = 4

\(\therefore\) Coefficient of x8 = 8C4 (2)4(-5)4

= 700000

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