2.x & gt0

3. Remove the absolute value of -5

4. Change the function to (x- 1) 2- 1 Because (x- 1) 2 > =0, the integer value is >; =- 1

So the minimum value is-1.

5. The minimum positive period is 2π/2= π.

6.0 odd function has the property of f(x)=-f(-x), so the bonus is 0.

7. Get 2A first, and then add the corresponding values of each position of the matrix to get {5 0.

0 3}

8. Substitute the value of 2i into the equation, and you can get b=0.

9.2 using AC/SIN B=BC/SIN A, the angle B = 45 can be obtained.

10.Cos x

COS X=-3/5，sin2x = 2sinx。 If you substitute Cosx into SIN X, you can find the value of con X.

SIN 2X=24/25

1 1.3 1 first calculate A=3A+ 1, that is, substitute A=3 to calculate A= 10, then calculate N= 1, and then judge the condition N = 1

12. If there is a problem, we can get the coordinate of the center of the circle as (1 0), then the original standard equation is (x-1) 2+y 2 =1.