For the term without XY in 5x ^ 2 + 3xy + 4y-2kxy + 4Y, find K

For the term without XY in 5x ^ 2 + 3xy + 4y-2kxy + 4Y, find K

=5x^2+(3-2k)xy+8y
∵ without XY
∴3-2k=0
∴k=3/2

Let f (x, y) = | XY |, prove that (1) f (x, y) is continuous at point (0,0); and (2) f (x, y) has two partial derivatives at point (0,0)
Let f (x, y) = | XY |, prove that (1) f (x, y) is continuous at point (0,0); (2) two partial derivatives of F (x, y) exist at point (0,0); (3) f (x, y) is nondifferentiable at point (0,0)

Given that the equation x2m2 + Y22 + M = 1 represents an ellipse with focus on the x-axis, then the value range of M is______ ．

The focus of the ellipse is on the x-axis 〈 M2 ＞ 2 + m, that is, m2-2-m ＞ 0. The solution of M ＞ 2 or m ＜ - 1 and ∵ 2 + m ＞ 0 〉 m ＞ - 2 〉 m is m ＞ 2 or - 2 ＜ m ＜ - 1, so the answer is m ＞ 2 or - 2 ＜ m ＜ - 1

Mathematics problem: function f (x) = cosx + SiNx, X belongs to R, what is the minimum value of F (x)?

F (x) = SiNx + cosx = radical 2 * sin (x + π / 4), so the minimum value of F (x) is negative radical 2

If the line y = - 2x-1 intersects with the line y = 3x + m in the third quadrant, please determine the value range of the real number M

In this paper, we obtain that x = - (M + 1) / 5
In the third quadrant, X and y have to be equal

It is proved that the function f (x) = the square of x-x is an increasing function in the interval (1 / 2, + ∞)

The derivative function f '(x) = 2 * X-1, in the interval you give, the derivative is greater than zero, so f (x) is an increasing function in the interval you give
Child, what grade are you in now? You didn't learn math well

How long is the edge of the cube? If you put it into the cube box with the edge length of an integer centimeter
What is the minimum edge length of the box?

The cube of 2 is 8, the cube of 3 is 27, 8 + 27 = 35
35 to the third power?
The minimum edge length is 4

If the function f (x) = ax & # 178; - (3a-1) x + a increases on (1, + ∞), what is the value range of real number a?

If the function f (x) = ax ^ 2 - (3a-1) x + A ^ 2 is an increasing function on [1, + ∞), find the value range of real number a
1) If a = 0
f(x)=x
On [1, + ∞) is an increasing function
2) A is not equal to 0
Then the axis of symmetry is x = (3a-1) / 2A = 3 / 2-1 / 2A
a> 0, the function opens up
The increasing interval is (3 / 2-1 / 2a, + ∞)
Only 3 / 2-1 / 2A "1
Solve 0

It is known that a and B are opposite to each other, C and a are reciprocal to each other, and the absolute value of X is 5
Try to find the value of X - (a + B + CD) + |a + B | + |3-cd |

a. If B is opposite to each other, then a + B = 0
c. If D is reciprocal to each other, then CD = 1
If the absolute value of X is 5, then x = - 5 or 5
x-(a+b+cd)+|a+b|+|3-cd| =x-(0+1)+0+2 =x+1
Get - 4 or 6

How do scientific calculators calculate logarithmic functions
My Casio fx-82es

Isn't it very simple? A = 10 ^ - 9.4