binomial coefficient

Question

Comments

x(1 + x + x^2 + ....+ x^4) x^2( 1 + x + x^2+ ...)^5

(1-x^5)/(1-x)* 1/(1-x)^5

= 1-x^5 *(1/(1-x)^6)

find coefficient of x^17

answer will be 22C17 - 17C12

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it should be  x^10 ( 1 + x + x^2+ ...)^5  not  x^2( 1 + x + x^2+ ...)^5 after taking out common

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Manu Thakur Sir shouldn't ,x¹⁰ should be coming out from second expression?

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I'm getting 185

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2751?

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sorry, i didn't see the power 5. let me correct my comment.

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x(1 + x + x^2 + ....+ x^4) x^10( 1 + x + x^2+ ...)^5

(1-x^5)/(1-x)* 1/(1-x)^5

= 1-x^5 *(1/(1-x)^6)

find the  coefficient of x^9

answer will be 14C9 - 9C4.

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@Manu Thakur

So, the answer will be 1876??

Answer 1

x(1 + x + x^2 + ....+ x^4) x^10( 1 + x + x^2+ ...)^5

(1-x^5)/(1-x)* 1/(1-x)^5

= 1-x^5 *(1/(1-x)^6)

find the  coefficient of x^9

answer will be 14C9 - 9C4.