Finding the extremum of function f (x, y) = XY (x ^ 2 + y ^ 2-1) with higher numbers

Finding the extremum of function f (x, y) = XY (x ^ 2 + y ^ 2-1) with higher numbers

Let f (x, y) = z = x & # 178; + Y & # 178; - 1
The results are as follows:
∂z/∂x=2x=0,x=0,
∂z/∂y=2y=0,y=0,
A stationary point (0,0) is obtained
A=∂²z/∂x²=2
B=∂²z/∂x∂y=0
C=∂²z/∂y²=2
When AC-B & # 178; 0, A0, a > 0, the minimum value
The results are as follows:
(0,0), AC-B & # 178; > 0, a > 0, minimum
above!
Hope to help you!

It is known that three planes intersect each other and there are three intersecting lines. Verification: if two of the three intersecting lines intersect at one point, then the three intersecting lines intersect at one point

Let α and β intersect L1, α and γ intersect L2, β and γ intersect L3
L1 and L2 intersect at point P
Because P ∈ L1, so p ∈ β
Similarly, P ∈ γ
So p is the common point of β and γ
So p is on line L3
So L1, L2, L3 intersect at P
Get proof

Solving equation 3 / 4x-25% = 2
3 / 4x-25% = 2 is the result equal to 4 or 3?

Solving equation 3 / 4x-25% = 2
3/4X-25%=2
3/4X=2+0.25
3/4x=2.25
x=9/4*4/3
x=3

How to calculate minus ninety-nine and forty-nine times twenty

The absolute value of the original formula is divided into (100-1 / 40) * 20 = 2000-0.5 = 1999.5
So it was - 1999.5

It is known that A.B.C is the three internal angles of Δ ABC and satisfies 2sinb = Sina + sinc. Let B be the maximum value of B0 (1) and find the value of B0

Analysis:
According to the sine theorem, it can be concluded that:
a/sinA=b/sinB=c/sinC
Given that 2sinb = Sina + sinc, then 2B = a + C
The square of both sides of the above formula is: 4B & # 178; = A & # 178; + 2Ac + C & # 178;
From the cosine theorem, we get: B & # 178; = A & # 178; + C & # 178; - 2Ac * CoSb
Then: 4 (A & # 178; + C & # 178; - 2Ac * CoSb) = A & # 178; + 2Ac + C & # 178;
That is 8ac * CoSb = 3A & # 178; + 3C & # 178; - 2Ac
So: CoSb = (3a & # 178; + 3C & # 178; - 2Ac) / (8ac)
For a > 0, C > 0, the mean value theorem is: A & # 178; + C & # 178; ≥ 2Ac
Then: CoSb ≥ (6ac-2ac) / (8ac)
That is, CoSb ≥ 1 / 2 (if and only if a = C)
Easy to know ∠ B ≤ 60 degree
So the maximum value of angle B is B0 = 60 degrees

(1234+1)*6788-1234*(6788+1)
How can it be reduced to 6788-1234? What's the formula or how

(1234+1)*6788-1234*(6788+1)
You can get
1234 * 6788 + 6788 * 1 - 1234 * 6788 + 1234 *1
Then 1234 * 6788 can be offset
At the end of the day, only one was left
6788-1234
See?

Given that the vertex of the parabola y = x2-8x + C is on the X axis, then C is equal to ()
A. 4B. 8C. -4D. 16

According to the meaning of the question, we get 4C − (− 8) 24 × 1 = 0 and C = 16

Calculation of 32 × 3.14 + 5.4 × 31.4 + 0.14 × 314 by factorization=______ ．

32×3.14+5.4×31.4+0.14×314，=0.32×314+0.54×314+0.14×314，=314×（0.32+0.54+0.14），=314×1，=314．

As shown in the figure, in △ ABC, the bisector of ∠ ABC and ∠ ACD intersects at point O. try to explore the relationship between ∠ BOC and ∠ A and prove your conclusion
Tonight, not too late!

∠A+∠ABC+∠ACB=180°
∠ABC+∠ACB=180°-∠A
∠BOC+∠OBC+∠OCB=180°
∠BOC=180°-(∠OBC+∠OCB)
∠OBC=∠ABC/2
∠OCB=∠ACB/2
∠BOC=180°-(∠OBC+∠OCB)=180°-(∠ABC+∠ACB)/2=180°-(180°-∠A)/2=90°+∠A/2

(3 times 10 to get 30:30 minus 5 to get 25:5 minus 2 to get 3:10 minus 1 to get 9:3 times 9 to get 27:27 plus 2 to get 29) where's the other one

This question is similar to a question about hotels, but it turns into a number