20 13 mathematical answers for the senior high school entrance examination in Guangzhou, Guangdong

20 13 Guangzhou senior high school entrance examination mathematics reference answer:

I. DACBD、CBDAB

2. 1 1, 7 12, 13,

14、 15、8 16、

Third, 17,

18、6

19, original type

20, omitted

2 1、( 1)

(2)500

(3)

22、( 1) 15.9

(2) Ship B arrives first.

23、

(2)

Omit 24( 1)

(2)①

② There are two, AE ed = 4.

25、( 1)

(2)B is in the fourth quadrant. The reasons are as follows

∵

So parabola and axis have two intersections.

Because the parabola does not pass through the third quadrant

So, the vertex is in the fourth quadrant.

(3)∵, on the parabola, ∴

It is easy to get b and c by substituting them into the linear analytical formula.

solve

It's easy to know when drawing, C is on the right of A,

At that time,