1. In (2pi, 3pi), the same angle as the terminal edge of - (7 / 8) Pi is? 2. If the end of angle a falls on the line y = 3x, then the value of COS A is? 3. Let the terminal edge of angle A and the terminal edge of (2 / 3) PI be symmetric about the Y axis and a belong to (- 2pi, 2pi), then a= 4、sina+cosa=(1/3),tan^2a+cot^2a=? My foundation is poor,

1. In (2pi, 3pi), the same angle as the terminal edge of - (7 / 8) Pi is? 2. If the end of angle a falls on the line y = 3x, then the value of COS A is? 3. Let the terminal edge of angle A and the terminal edge of (2 / 3) PI be symmetric about the Y axis and a belong to (- 2pi, 2pi), then a= 4、sina+cosa=(1/3),tan^2a+cot^2a=? My foundation is poor,

There is a problem in this question. The angles in (2 π, 3 π) are the first and second quadrants, and (7 / 8) π is the third quadrant. How can their terminal edges be the same?
2,y=3x,tga=3 1+tg^2a=1/cos^2a=10
1/cosa=√10 cosa=√10/10
3. The final edge of (2 / 3) Π is in the second quadrant, and the angle about Y-axis symmetry is in the first quadrant a = Π / 3
4,sina+cosa=1/3...(1)
（sina+cosa)^2=1/9 2sinacosa=-8/9
sinacosa=-4/9
(sina-cosa)^2=(sina+cosa)^2-4sinacosa
(sina-cosa)^2=1/9+16/9=17/9
sina-cosa=±√17/3...(2)
[(1) + (2)] 2, [(1) - (2)] 2
sina=（1+√17）/6
cosa=（1-√17）/6
tg^2a+ctg^2a=(tga+ctga)^2-2
(sina/cosa+cosa/sina)^2-2
Substitute the values of sina and cosa into:
=49/16
Solving trigonometric function problems
Given that the angle a is 30 degrees and the length of the opposite side of angle a is 1, find the value range of ABC side length of triangle
Solving quadratic equation with cosine theorem
Solving trigonometric function exercises
cos(pai/6-@)=a(a
Cos (5pai / 6 + @) = - cos (PAI - (5pai / 6 + @)) come out, the root sign three has the sign Q, it's hard to write, dizzy
sin(2pai/3-@)=0.5qcos@+0.5sin@；
Cos (PAI / 6 - @) = 0.5qcos @ + 0.5sin @; it's incredible. I'm a little bit, but it's equal. It seems very different,
In the plural of countable nouns, the word ending with "O" will add "es" or "s" if it has a living body. What about the word ending with "O"?
The living plus es!
Inanimate of course plus s la!
There is life: potatoes, for example
Hero
Inanimate:
For example, photo
Words ending in ch, sh
Duo, NOUN
beach,bruch,lunch,watch,touch,bitch,
dish,fish,flash,English
Nouns ending with s, x, SH, Ch
J brothers and sisters, help me! Thank you!
10 for each word, thank you
bus class watch box class tax bush batch beach catch peach
In fact, there are many words that have the nature of both nouns and verbs
S, SH, C, CH, X. is there anything else
Almost right, the general ending is hard sound will add es, soft sound plus s
There will always be exceptions
For example, the plural of sky is sky
Generally speaking, if you can't pronounce by adding s, and then you pronounce more smoothly by adding es, then you should add es
Just like the past tense plus ed, there are some rules but not absolute, there are always exceptions
The best thing to do is to look more familiar and write it down
That's about it.
Add es at the end of S, x, SH, CH, O and go to s, x, SH, CH, O
No
When a noun ending with the letter S, SH,. Ch or X becomes plural, add?
Es
What are the vowels with a
I'm going to take the high school entrance examination. Don't teach me vowel pronunciation. I don't know anything about it. I just need several common words.
I've said a few words. You are sweating to death. I just want some words that don't use an before vowels. I'm really defeated by you.
In the senior high school entrance examination, we often test the words of universe, useful, Europe, European, and most (very unpopular) words that do not start with a, e, I, O, U. but in the senior high school entrance examination, we often test (very popular, because of special) words that add an, such as hour, honey, and most (unpopular) words that start with a, e, I, O, U
It's usually U
The most commonly used word is universe
Europe is an example. Because the first sound in the phonetic sign is / ju: /, which does not start with a vowel phoneme, a is used instead of an.
A,H,J,K