The inverse sequence function y = K / X (KY1 > 0 > Y3) is known C.y3>0>y1>y2 D.y3>0>y2>y1

The inverse sequence function y = K / X (KY1 > 0 > Y3) is known C.y3>0>y1>y2 D.y3>0>y2>y1

Option B

Ask a linear algebra question: X1 x2 X3 is the solution of X * 3 + QX + P = 0, then the determinant X1 x2 X3 X3 X1 x2 X3 x1
The answer is zero,

X1 x2 X3 X3 X3 X1 x2 x3 x1c1 + C2 + c3x1 + x2 + X3 x2 X3 X1 + x2 + X3 X1 x2 X1 + x2 + X3 X3 x3 x1r2-r1, r3-r1x1 + x2 + X3 x2 X3 0 x1-x2 x2 x2-x3 0 x3-x2 x1-x3 determinant = (x1 + x2 + x3) [(x1-x2) (x1-x3) - (x2-x3) (x2-x3)] = (x1 + x2 + x3) (x1 ^ 2 -

The condition that two vectors are parallel, the condition that two vectors are perpendicular

a=λb
Then a ‖ B
Vector method a (x1, Y1) B (X2, Y2)
If x1y2 = y1x2
Then a ‖ B
If a * b = x1x2 + y1y2. = 0
Then a ⊥ B

How to determine whether two vectors are parallel or vertical

Vector a = (x1, Y1), vector b = (X2, Y2),
The necessary and sufficient condition of a ‖ B (or equivalent) is that x 1y 2-x 2Y 1 = 0;
The necessary and sufficient condition of a ⊥ B (or equivalent to) is x1x2 + y1y2 = 0;