|X-Y | = under the root sign (x + y) twice + () The answer is - 4xy, who can tell me,

|X-Y | = under the root sign (x + y) twice + () The answer is - 4xy, who can tell me,

(x+y)2=x2+y2+2xy
Add (- 4xy) = x2 + y2-2xy = (X-Y) 2
And then we're going to square it up to | X-Y|

Let f (x) = (1 + x) ∧ 6 (1-x) ∧ 5, then the coefficient of X ∧ 3 in F '(x) is

Hello!
f（x）=（1-x²）^5（1+x）
Because the previous bracket can only produce even number of times, so the cubic term can only be produced from the square term of the previous bracket
5C1*（-1）=-5
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(2010 - Changchun three mode) set f (x) = (2x+1) 6, then the coefficient of X3 in F (x) derivative function f '(x) expansion is ().
A. 960B. 480C. 240D. 160

According to the meaning of the question, f (x) = (2x + 1) 6, then f ′ (x) = 12 (x + 1) 5, combined with binomial theorem, the term containing X3 is 12c52 (2x) 3 = 960x3; so a