A square + AB + b square = 0, then a of B

A square + AB + b square = 0, then a of B

a^2+ab+b^2=0,
——》(a/b)^2+(a/b)+1=0,
——》a/b=(-1+-√3i)/2.

If a > b, then B__ At 0, ab

b＜0

What is the transition matrix from the base B1 = a1 + A2 + a3, B2 = Q2, B3 = A3 of R3 to the base A1, A2, A3?

(b1,b2,b3) = (a1,a2,a3)K
K=
1 0 0
1 1 0
1 0 1
k^-1=
1 0 0
-1 1 0
-1 0 1
(b1,b2,b3)K^-1 = (a1,a2,a3)
K ^ - 1 is the required value

If the sum of the top and bottom of the isosceles trapezoid ABCD is 6 and the acute angle between the two diagonals is 60 °, the area of the isosceles trapezoid is___

There are two answers: 3 √ 3 or 9 √ 3. Because the question does not specify whether the angle of 60 ° is the angle corresponding to the hypotenuse or the angle corresponding to the bottom edge, the process is as follows:

Let X and Y belong to R, and lgx + lgY = LG (x + y), find the minimum value of X + 4Y
That's how I understand it
lgxy=lg(x+y)
Xy = x + Y > = 2 radical XY
(xy)^2>=4xy
xy>=4
Then x + 4Y > = 2 radical x * 4Y
It's > = 8
.
What's wrong

X + y ≥ 2 √ (XY) is equal if x = y
If x + 4Y ≥ 2 √ (4xy) takes the equal sign, the condition is x = 4Y
The two conditions are not the same. You can't bring them in

School to paint a classroom, this classroom 9 meters long, 6 meters wide, 5 meters, the classroom doors and windows area of 32 square meters, according to paint 1 square meter need 500 grams of lime
How many kilograms of lime does it take to paint the walls and ceiling of the classroom?

What is the area of the ceiling
9 × 6 = 54 (M2)
What is the area of the four walls
(9 × 3.5 + 6 × 3.5) × 2 = 105 (M2)
What is the area to be painted
105 + 54-32 = 127 (M2)
Lime is needed
500 × 127 = 63500 (g) = 63.5 (kg)

The trajectory equation of the midpoint of the chord passing through a point (0, 2) in the ellipse X225 + y216 = 1 is ()
A. 16x225+(y−1)2＝1B. 25x216+(y−1)2＝1C. x225+(y−1)2＝1D. x216+(y−1)2＝1

Let the coordinates of the two ends of the chord be (x1, Y1), (x2.y2) and the coordinates of the middle points of the chords be (x, y). The slope of the straight line where the chord is located is kx2125 + y2116 = 1x2225 + & nbsp; y2216 = 1. By subtracting the two formulas, we can get 125 (x1 + x2) (x1-x2) + 116 (Y1 + Y2) (y1-y2) = 0, that is, 2x25 + 2y16k = 0 and ∵ k = y − 2x

Two triangles of equal area can be combined into a parallelogram

Wrong
[if two triangles of the same shape (i.e. congruent) can form a parallelogram]

Ellipse x ^ 2 / A ^ 2 + y ^ 2 / b ^ 2 = 1 E = √ 3 / 2 ellipse and straight line x + 2Y + 8 = 0 intersect P and Q tangent | PQ | = √ 10 to solve elliptic equation

e=√3/2=c/a→b²=a²/4①
Straight line and ellipse
→2x²+16x+64-a²=0
→x1+x2=-8,x1x2=32-a²/2
→|x1-x2|=√(a²-64)
→PQ=√(1+k²)*|x1-x2|=√2
It can be carried in K and calculated

If the circumference of a rectangle is 4A + 2B and the width is A-B, its length is______ ．