From the secant ABC of a (4,0) leading circle x 2 + y 2 = 4, the trajectory equation of midpoint P of chord BC is obtained

From the secant ABC of a (4,0) leading circle x 2 + y 2 = 4, the trajectory equation of midpoint P of chord BC is obtained

Method 1: let P (x, y) be connected with OP, then op ⊥ BC (2) when x ≠ 0, Kop · KAP = - 1, that is, YX · YX − 4 = - 1, that is, X2 + y2-4x = 0 (8) when x = 0, the coordinates of point P (0, 0) are the solution of the equation (★) (12 points) BC point P of

Given that x + 4Y = 6Z and 3x-4y + 2Z = 0, find the value of 2x + 3Y / Z

3x-4y + 2Z = 0 is 3x-4y = - 2Z and X + 4Y = 6Z
Multiply x + 4Y = 6Z by 3 to get 3x + 12Y = 18z, and combine 3x-4y = - 2Z to get y = 5Z / 4
So 2x + 3Y / z = 13 / 4

Given that x + 4Y = 6Z and 3x-4y + 2Z = 0, find the value of 2x + 3Y divided by Z

x+4y=6z (1)
3x-4y+2z=0 (2)
(1)+(2) 4x=4z x=z
Substituting (1) y = 5Z / 4
So 2x + 3Y divided by z = (2Z + 5Z / 4) / z = 2 + 5 / 4 = 13 / 4

Given {2x + 3Y = Z, 3x + 4Y = 2Z + 6 and X + y = 3, then the value of Z is,

y=3-x
Deformation 1: 2x + 3 (3-x) = Z
2x+9-3x=z
-x+9=z
Take z = - x + 9 into 2:3x + 4 (3-x) = 2 (- x + 9) + 6
3x+12-4x=-2x+18+6
-x+2x=24-12
x=12
So z = - 12 + 9 = - 3

Matlab solution equation, x + 2Y + Z = 1 2x + y-2z = 3 3x-4y + 2Z = 9

>> [x y z]=solve('x+2*y+z=1,2*x+y-2*z=3,3*x-4*y+2*z=9')
x =
75/37
y =
-23/37
z =
8/37
>>

[biochemistry] 9. If heavy metals are used to precipitate protein with PI of 8, the pH value of the solution should be A.8B. > 8C. < 8D. ≤ 8e. ≥ 8

Because heavy metals are positively charged, they need to bind to negatively charged proteins
The charge of protein band is related to the isoelectric point,

1 / 2x + 3 (- 2Z + y) - (1 / 3x-4y-5z) calculation

=1/2x-6z+3y-1/3x+4y+5z
=(1/2x-1/3x)+(3y+4y)+(-6z+5z）
=1/6x+7y-1z

Are there only two mathematical constants PI and E?
Are there any other constants besides these two?
In letters, not numbers.

The five constants in mathematics are: 0,1, π, e, i
And e ^ (I Π) + 1 = 0
As long as the constant value is constant
Of course, there are other meaningful constants, such as the golden section ratio,
But they are not as common as the above five

How to solve the equation 2x + 2Y + 2Z = 30,2x + 3Y + 4Z = 47,3x = 4Y + 5Z = 62

Suppose that 3x = 4Y + 5Z = 62 is 3x-4y + 5Z = 62, then
2x+2y+2z=30 x+y+z=15 x=15-y-z
Substituting: 2x + 3Y + 4Z = 47 30-2y-2z + 3Y + 4Z = 47 y = 17-2z
Take back the above formula: x = 15-17 + 2z-z = Z-2
The above two are substituted into 3x-4y + 5Z = 62 3z-6-4 * 17 + 8Z + 5Z = 62 16Z = 136 z = 8.5
x=6.5 y=0 z=8.5

What exactly does PI in PI lab mean?

Principal investigator is the largest "project director" in the lab
Laboratory research team leader responsibility system