Senior high school mathematics about circle Solve the equation of the circle with the smallest area at the intersection of the line 2x + y + 4 = 0 and the circle x * + y * + 2x-4y + 1 = 0 I just don't understand "the equation of the smallest circle"?

Ll first of all, you should know that the garden passes through the intersection of the straight line and the circle
Three points can determine a circle. You only have two points now. So there are many circles passing through the two intersections
You're looking for the smallest one. That actually means
When the diameter of the required circle is equal to the distance between the two intersections, the area of the required circle is the smallest. If it is smaller, it will not pass through the two intersections
Maybe it's a bit messy. Just draw a sketch

Find the number 0 1 2 3 4 5 to form a number without repetition
1. Find the number of six digits
2. Find the number of odd numbers that make up six digits

1. Find the number of six digits
If we want to exclude the case of 0 as the first place, we should count the number
=Total permutation of 6 - Total permutation of 5
= 6*5*4*3*2*1 - 5*4*3*2*1 = 720 - 120 = 600
2. Find the number of odd numbers that make up six digits
If the number of digits is 1, 3 and 5, the remaining five digits are arranged completely, minus the case that the first digit is 0
= （5*4*3*2*1 - 4*3*2*1）*3
= （120 - 24）*3
= 288

If the meaning of "" is
If the meaning of "" is a * b = AB divided by a + B, find the value of 2 * (- 3) * 4

First calculate 2 * (- 3), and then calculate the result with 4
2*（-3）*4
=[-6/(-1)]*4
=6*4
=24/10
=2.4

() times (- 2) equals 0.8

(- 0.4) times (- 2) equals 0.8

Solving equations 3x-5y = 10 ① 2x + 10Y = 4 ②

X = 3, 1 / 5

The store stipulated that three empty bottles should be replaced by one bottle of soda water for recycling. After a person bought 10 bottles of soda water, he took the empty bottle to replace it with soda water and asked him if he could drink it altogether?

There are 10 bottles of soda
Take nine water bottles for three
Take another three water bottles for one
Then ask someone else to borrow a water bottle and replace it with two of their own
Finally, return the bottle to the borrower
Conclusion: 10 + 3 + 1 + 1 = 15

Given x + 2Y = 1, find the minimum value of 1 / x + 1 / y
If and only if x + 2Y = 1 and which of the other conditions is true, take the minimum value?

1/x+1/y
=(x+2y)/x+(x+2y)/y
=1+2y/x+x/y+2
=3+2y/x+x/y
≥3+2√2
if and only if
When 2Y / x = x / y, the equal sign holds
here
x=√2y
Substituting x + 2Y = 1
The solution is x, y

It's 26 yuan for two snacks and one drink. It's 18 yuan for one snack and three drinks. How much is one snack and one drink?
26-18 = 8 is 8 yuan more for a snack than a drink

Set X Yuan for a snack and Y yuan for a drink
2X+Y=26
X+3Y=18
The solution of the quadratic equation is: x = 12, y = 2

Simplify the 5th power of [(x + y) to the 3rd power] and the 2nd power of [(x + y) to the 7th power]

The fifth power of [(x + y) to the third power] and the second power of [(x + y) to the seventh power]
=[(x + y) to the 15th power] * [(x + y) to the 14th power]
=15 + 14 power of (x + y)
=The 29th power of (x + y)

The distance between a and B is 200 kilometers. Car a runs 40 kilometers per hour from place a to place B. after car a runs for 1.5 hours, car B runs to place a every hour
Driving 30 kilometers, how long did car B run before meeting car a

(200-40 × 1.5) / (40 + 30) = 2 hours

Senior high school mathematics about circle Solve the equation of the circle with the smallest area at the intersection of the line 2x + y + 4 = 0 and the circle x * + y * + 2x-4y + 1 = 0 I just don't understand "the equation of the smallest circle"?