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how do i find the constant term in the expansion of (2x^2-1/x)^6

 Feb 7, 2017
 #1
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It's    60.

 

Using the binomial theorem,the fifth term is (6)(5)(4)(3)(2x^2)^2(1/x)^4    /  4!

=(6)(5)(4)(3)(4x^4)(1/x^4)     /4!

=(6)(5)(4)(3) (4)       /4!

= (6)(5)(4)(3)  (4)/     (4)(3)(2)

=(6)(5)(4)  /(2)     = (6)(5)(2)  = 30 x 2  = 60

 Feb 7, 2017
 #2
avatar+130466 
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The constant  willl occur at the 5th  term in the binomial expansion of this  =

 

C(6,4) * (2x^2)^2 * (1/x)^4  =

 

15 (4x^4) (1/x^4)  =

 

15* 4   =

 

60

 

 

cool cool cool

 Feb 7, 2017
 #3
avatar+26396 
+5

how do i find the constant term in the expansion of (2x^2-1/x)^6

 

(2x21x)6=(2x31x)6=(2x31)6x6=1x6(2x31)6

 

The constant  term is at the 5th term in the binomial expansion:

1x6(64)(2x3)2|(64)=(664)=(62)=1x6(62)(2x3)2=1x6(62)4x6=4(62)=46251=435=60

 

laugh

 Feb 7, 2017

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