A small question extra points to ask a few questions can add points online, etc

Due to the reversibility of light.

What is Avatar? What is a real image?

Real image: The refraction emitted by the object point through the lens, all the refractive lines can converge at a point, the point is called the real image point of the object point, and the set of all the real image points is called the image of the object. The characteristics of the real image are: the convergence of the actual light, the inverted, the opposite side, can be formed on the screen.

Virtual image: The light emitted by the object point, the intersection point of the reverse extension line of the refractive line refracted by the lens is called the virtual image point of the object point, and its set is called the virtual image of the object. The characteristics of the virtual image are: it is not the convergence of actual light, it is upright, and the same side cannot be formed on the screen.

To put it simply: the real image refers to the image that can be displayed on the image screen, and the virtual image is the image that cannot be displayed on the image screen.

The difference between a real image and a virtual image is that the actual light of the real image is gathered, and the virtual image is formed by the intersection of the reverse extension line of the actual light, and the real image can be presented on the light screen, while the virtual image cannot.

The eye can sense light, and when the plane mirror reflects the light into the human eye, according to the reversibility of the light, the virtual image can be seen against the light.

What you see is yourself, not an illusion.

It's just that the direction of the light changes after being reflected by the plane mirror, and people judge by experience that there is a person in the plane mirror, and that person does not exist, so it is the so-called virtual image, and in fact, what you see is yourself.

Why can we see objects? It is because the object reflects the light, and the light hits our eyes to see. It's the same with mirrors, but the light shines on the object first, then reflects back on the mirror, and the mirror reflects back to our eyes.

Due to the specular reflection of light, the light is reflected to the human eye, so the virtual image is seen.

Because you exist objectively, and the wavelengths of reflection on your body are in between, if you are in pure black and no light, you can't even see your own body...

Solution:1(2a^6-a^3)/(a^3/2)=a^3(2a^3-1)/(a^3/2)=2(2a^3-1)=4a^3-2

a-1/a)^2=(a+1/a)^2-4*a*(1/a)=4^2-4=16-4=12

cd=ac-da=5-2=3

4.Solution: The distance is equal, know the speed ratio, find the time ratio, and the time ratio between Xiao Ming and Xiao Li is:

So Xiaoli time: 1 (6 5-1) = 1 (1 5) = 5 minutes 600 5 = 120

I didn't understand the first question.

The second question. a + a one) squared = 16

The square of a + 2 + the square of one part of a = 16

The square of a + the square of a part of a = 14

a-a-1/a) square = the square of a + 1/a's square - 2 = 14-2 = 12 The third question.

ab=ad=2

ac=5cd=ac-ad=5-2=3

Angle BAC = Angle EAC = 140 degrees.

In the fourth question, Xiao Ming's typing speed is set to x

Xiaoli speed. 600 divided by x-600 divided by.

Multiply by 600 = 600x+ squared.

720x-600x=squared.

So Xiaoli's speed is 120 per minute.