If the product of (x + m) and (x's square + MX + 3) does not contain the quadratic term of X, then the coefficient of the first term of X in the product is

If the product of (x + m) and (x's square + MX + 3) does not contain the quadratic term of X, then the coefficient of the first term of X in the product is

(x+m)(x^2+mx+3)
The quadratic coefficient of X is
The product of X and MX the product of M and x ^ 2
mx^2+mx^2=2mx^2
∵ without quadratic term
∴m=0
The original form is changed into
x(x^2+3)
The coefficient of the first term of X is 3

(x ^ - 2 times - y ^ - 2 times) / (x ^ - 2 times + y ^ - 2 times) = y ^ 2-x ^ 2 / y ^ 2 + x ^ 2, right (x ^ - 2 times + y ^ - 2 times) / x ^ - 2 times * y ^ - 2 times = y ^ 2 + x ^ 2, right

(x ^ - 2 times - y ^ - 2 times) / (x ^ - 2 times + y ^ - 2 times) = y ^ 2-x ^ 2 / y ^ 2 + x ^ 2 pairs
(x ^ - 2 times + y ^ - 2 times) / x ^ - 2 times * y ^ - 2 times = y ^ 2 + x ^ 2 pairs

Then the variable x obeys n (0,1) distribution, y = x ^ 2, and the correlation coefficient of X and Y is calculated

p=cov(x,y)/[√D(x)*√D(y)]cov(x,y)=E(x*y)-E(x)*E(y)=E(x^3)-E(x)*E(x^2)=E(x^3)=∫∞(x³*e^(-x²/2)/√(2π))D(x)=1,D(y)=D(x^2)=E(x^4)=∫∞(x^4*e^(-x²/2)/√(2π))