Let real numbers x, y, Z satisfy 2x ^ 2 + y ^ + 5Z ^ 2 = 3, then x + 2Y + 3Z has the maximum value of

Let real numbers x, y, Z satisfy 2x ^ 2 + y ^ + 5Z ^ 2 = 3, then x + 2Y + 3Z has the maximum value of

Minimum or maximum?
Let f (x) = x + 2Y + 3Z
The minimum value of F (x) is - √ (189 / 10), and the maximum value of F (x) is √ (189 / 10)
According to Cauchy Inequality: (2x ^ 2 + y ^ 2 + 5Z ^ 2) (1 / 2 + 4 + 9 / 5) ≥ (x + 2Y + 5Z) ^ 2
The equal sign holds if and only if 2x ^ 2 / 0.5 = y ^ 2 / 4 = 5Z ^ 2 / (9 / 5). To minimize f (x), of course, x, y, Z are all negative numbers, that is, the same sign;
If y = 4x, z = 6 / 5x, the equal sign holds,
From the above formula: | x + 2Y + 5Z | ≤ √ (3 × 63 / 10) = √ (189 / 10)
-√（189/10）≤x+2y+5z≤√（189/10）
The maximum value of X + 2Y + 5Z is √ (189 / 10), and the minimum value is - √ (189 / 10)

Let x1, X2 If S2 = 0, then x1, X2 The condition that xn should satisfy is______ ．

According to the meaning of variance, if the variance is 0, there is no fluctuation, so there is: X1 = x2 = =So fill in X1 = x2 = =xn．

Given a set of data x1x2 The variance of XN is the square of S, a new set of data ax1 + 1, AX2 + 1 The variance of axn + 1

Given a set of data x1x2 The variance of XN is the square of S,
A new set of data ax1 + 1, AX2 + 1 The variance of axn + 1 = (as) squared

Given a set of data x1, X2 The variance of XN is S2, then a new set of data ax1 + 1, AX2 + 1 The variance of axn + 1 (a is constant, a ≠ 0) is______ Note: S2 = 1n [(x1 -. X) 2 + (X2 -. X) 2 + +（xn-.x）2]）

∵ a set of data x1, X2, X3 The variance of XN is S2, a set of new data ax1 + 1, AX2 + 1, AX3 + 1 The variance of axn + 1 is A2 · S2