phương trình \(cos^22x+cos2x-\frac{3}{4}=0\)có nghiệm là ??

các giá trị \(x\in\left[-\pi;\pi\right]\)để cot x = - 1

giải phương trình \(\cos^2x-2\cos x-3=0\)

giải phương trình \(\sin x\times\left(2\cos x-\sqrt{3}\right)=0\)

1, They spent more money , they had to work harder

The more..........

2, People thought that the cover was made of iron

The cover.............

3, It's thought that the accident was caused by human error

The accident is.................

4, '' I think you should try the chicken marengo '' said the waiter

The waiter recommended ..............

5, this is the most delicous cake i have ever tasted

I have ..................

1, You should take the train instead of the bus

If ...............

2, I'm sure that someone forgot to lock the door

Someone must ......................

3, The course finished with a big party

At the end ..................

4, We invited a pop star onto the chast show , but he didn't turn up

The pop star .........................

5, although the said that she would come , i don't think she ever will

Despite ...............

tìm TXĐ

1 , \(y=\cos\frac{x+1}{x+2}\)

2, \(y=\sin\sqrt{x+4}\)

3, \(y=\cos\sqrt{x^2-3x+2}\)

1, Gary is the best guitarist in her class .

No one else ............................

2, Since the invention of computer , people have saved a lot of time .

Since the computer was.........................................

3, Jane gave me a present on my last birthday.

I was .............................

4, " Would you like a cup of coffee?"

He ...........................

5, It is a three - hour drive from Hanoi to Namdinh

It takes ......................

Tìm GTLN - GTNN

1, \(y=\sin x\) trên đoạn \(\left[\frac{-\pi}{2};\frac{-\pi}{3}\right]\)

2\(y=\cos x\)trên đoạn \(\left[\frac{-\pi}{2};\frac{\pi}{2}\right]\)

3, \(y=\sin x\)trên đoạn \(\left[\frac{-\pi}{2};0\right]\)

4, \(y=\cos x\)trên đoạn \(\left[\frac{1}{4};\frac{3}{2}\right]\)