Super high score for help!!!!!!! 30 points!!!

A total of 55 bags were taken out, and if there were no defective products, the total weight of these 55 bags: 400 55 = 22000 grams.

Now it is only 21,920 grams, which is less: 22,000-21,920 = 80 grams per bag of defective products is 20 grams less.

Therefore, the defective products taken out are: 80 20 = 4 bags.

According to the title, the fourth box is a defective product.

55 bags should be 55 * 400 = 22000g

The actual is 21920g

80g is missing, and a certain carton of milk powder is 20g less per bag

80 20=4 means that if there is less than 20g, take four bags out, that is, the fourth box.

From the trigonometric function and the differential product formula, we get:

y=cos（π/12-x）-cos(5π/12+x)=-2sin((π12-x+5π/12+x)/2)sin((π12-x-5π/12-x)/2)

2sin(π/4)sin(-x-π/6)√2sin(x+π/6)

0≤x≤π/2

6≤x+π/6≤(π2+π/6)

Then the minimum value of sin(x+6) is sin(6)=1 2, and the maximum value is sin(2)=1

Then the range of the function is [ 2, 2, 2].

It's been years since I graduated from high school. and the differential product formula are forgotten.

When I saw this question, I remembered my green years.

(6+1) 1=7 times of the shadow in a large circle area.

(2+5) 2=times of the shadow when the area of a small circle is small.

So the big circle: the small circle = 7::1

So the area of the small circle = square centimeters.

I saw your mailbox on the first floor, and it was sent to your mailbox.

Analysis: Each student was given an equal amount of colored pencils. There are 12 people in this activity group, 2 more than 10 people, and there are more colored pencils (25-5) = 20 sticks, 2 people have 20 sticks, and one person gets 10 sticks.

The column formula is (25-5) 12-10) = 10 (branches) per person

There are 10 12 + 5 = 125 (pieces).

Let each person divide x branches can have the equation: 10x+25=12x+5, and the solution is x=10, and each person can divide 10 branches, a total of 125 branches.