how do i find the constant term in the expansion of (2x^2-1/x)^6
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
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
(2x2−1x)6=(2x3−1x)6=(2x3−1)6x6=1x6⋅(2x3−1)6
The constant term is at the 5th term in the binomial expansion:
1x6⋅(64)⋅(2x3)2|(64)=(66−4)=(62)=1x6⋅(62)⋅(2x3)2=1x6⋅(62)⋅4x6=4⋅(62)=4⋅62⋅51=4⋅3⋅5=60