We come to the park with relaxed steps and happy mood?

We come to the park with relaxed steps and happy mood?

We came to the park with a light heart

What is the relationship between the size of two rational numbers and the absolute value of these two numbers?

When two rational numbers are positive, the absolute value of the number with large number is large;
When two rational numbers are negative, the absolute value of the large number is small

Inverse function of y = e ^ 2x

A:
The exchange of X, y positions leads to:
x=e^(2y)
We obtain 2Y = LNX, that is, y = (LNX) / 2, where x > 0

Xiaogang's mother spent 360 yuan on a sweater, accounting for 20% of the family's monthly expenses. How much did Xiaogang's family spend this month?

360 △ 20% = 1800 yuan a: Xiaogang spent 1800 yuan this month

The range of function ln (X-2) is

∵ domain
x-2>0
x>2
Using inverse function to calculate range
e^y=x-2
e^y+2=x
y=e^x+2
∵e^x+2>2
∴
x∈ R
Range R

When to use the method of objectivism to solve function problems in mathematics?

Get independent variable with given parameter range

Wang Fei goes to the mountain library to borrow books. He goes up the mountain at 3 kilometers an hour and returns from the original road at 5 kilometers an hour

(1 + 1) / (13 + 15) = 2 / 815, = 2 × 158, = 154 (km); a: the average speed up and down the mountain is 154 km

Let a be an antisymmetric matrix, B be a symmetric matrix, and prove that the square of a is a symmetric matrix; ab-ba is a symmetric matrix

A=-A^t,B^t=B
A^2=(-A)^t(-A)^t=(A^2)^t
So a ^ 2 is a symmetric matrix
(AB-BA)^t=(AB)^t-(BA)^t
=B^tA^t-A^tB^t
=B(-A)+AB
=AB-BA
So ab-ba is a symmetric matrix

When "None" and "neither" are the subjects, do you use the singular or the plural? There are several examples. Please help me to explain in detail why the singular or the plural is used
None of us has ever been to the US.
None of them are my friends.
None of the passengers are aware of the danger.
Neither of the books is of any use of me.
Neither are suitable for newspapers.

None can be plural or singular
Context
Neither must be singular
None of us has ever been to the US
None of them are my friends
They are all my friends, emphasizing a group of people, so plural
Neither are suitable for journalists

The bookstore brought in a batch of children's books. The first day they sold 1800 copies, the second day they sold 1 / 5 more than the first day, and the remaining 3 / 7 of the total. The third day they sold out. How many books are there

(1800 + 1800x1 / 5 + 1800) / (1-3 / 7) = 6930 copies
So there are 6930 books