After reading the story "reading for the rise of China", I was deeply inspired. How can I correct the wrong sentence?

After reading the story "reading for the rise of China", I was deeply inspired. How can I correct the wrong sentence?

In the absence of subject, add "I" before "read" or "deeply"

The teacher often encourages us to study and read well
RT.

The teacher often encourages us to study hard

What's cos15, sin15, tan50? Thank you,
What are cos15 degrees, sin15 degrees, tan50 degrees? Just keep one decimal place

cos15=(√6+√2)/4= 0.75968791285882 sin15=(√6-√2)/4 = 0.65028784015712 tan(50) = 0.27190061199763

How to understand average acceleration and instantaneous acceleration?
Can you summarize it in a simpler and more popular way

==The main points are all below. If you are not clear, please add LZ
definition:
The ratio of the change of velocity in a period of time to that in this period is the average acceleration in this period, a (bar) = Δ V / Δ t
The instantaneous acceleration is the average acceleration when the time tends to zero, that is, the derivative of velocity to time, a = LIM (Δ T) Δ V / Δ t = DV / dt
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Difference: for instantaneous acceleration, each instant can have different values; average acceleration is a description of the movement over a period of time
From the definition, only if every instantaneous acceleration is the same in a period of time, can these instantaneous accelerations be the same as the average acceleration in this period of time
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Popular meaning:
Acceleration is the rate of change of speed to time, which describes the speed of change
In other words, the instantaneous acceleration is the speed of a certain instant, and the average acceleration is the average speed of a period of time
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P. F = DP / dt = MDV / dt + VDM / dt = ma + VDM / DT, f = ma is only suitable for macro low speed

There are 176 chickens and rabbits in a farm. It is known that the total number of chicken feet is 214 more than that of rabbit feet. How many chickens and rabbits do you raise?

According to the meaning of the question, 2x-214 = (176-x) × 4, 2x-214 = 704-4x, & nbsp; 2x + 4x = 704 + 214, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 6x = 918, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 918 △ 6, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X

What degree is Tan equal to minus 2?
Anxious

No direct degree can be expressed as an inverse function
TT + arc Tan (- 2) or TT - arc Tan (2)
TT = 360 degrees
Sorry, I didn't check last time. I have the wrong number. Sorry!

The square of 5x = 4 minus 2x
The answer is X1 = 5 minus 1 + radical 21, X2 = 5 minus 1 - radical 21, but you guys give me the process

5x square = 4-2x 5x square + 2X-4 = 0 by the formula of quadratic equation of one variable x = - B ± √ b square - 4ac / 2A x = - 2 ± √ 2 square - 4 × 5 × (- 4) / 2 × 5 x = - 2 ± √ 4 + 80 / 10 x = - 2 ± 9.165 / 10x1 = - 2 + 9.165 / 10x1 = 7.165/10x1 ≈ 0.717x2 = - 2-9.165 / 10x2 = 11.165 /

If the point P (- 1-2a, 2a-4) is symmetric about the origin in the first quadrant, then the integer solution of a has ()
A. 1 B. 2 C. 3 d. 4

∵ the point P (- 1-2a, 2a-4) is symmetrical about the origin. In the first quadrant, a ∵ 1 − 2A ∵ 0, a ∵ 2A − 4 ∵ 0, a ∵ 12, a ∵ 2, a = 1 or 0

Let f (x) be an odd function with a period of 5 and f (- 1) = - 1, then f (11) =?

For odd functions, then f (- 1) = - f (1) = 1
Cycle 5
f(1)=f(6)=f(11)=1

Is y = x ^ 2 – 5x – 6 monotone interval function y = f (x) Zeng function or subtraction function

The axis of symmetry is a straight line, x = 5 / 2
It is a decreasing function on (- ∞, 5 / 2)
On [5 / 2, + ∞) is an increasing function