数学代考
数学final代考 1.Which of the following equations will have 2 as a root. ( )
A．x²+2x-x=0 B．x²-x-2=0 C．x²+x+2=0 D．x²+x-2=0
1.Which of the following equations will have 2 as a root. ( ) 数学final代考
A．x²+2x-x=0 B．x²-x-2=0 C．x²+x+2=0 D．x²+x-2=0
2.Translate y= (x+1)², 3 units rightwards, then 7 units upwards，then we get：___________________________________.
3.If the vertex is （3，-4）and a is 5, write the function in vertex form .
- Solve the quadratic equations:
(1) x2 – 7x – 8＝0 (2) x2＋8x＝20
(3) 16 x2 – 4＝0 (4) x2＋8x＋16 = 0
(5) 6x2 -11x+4=0 (6)（2x-3）2-2（2x-3）=0
- How many of the following has central symmetry? （ ）
6.As shown in the figure，in ⊙O,OA⊥BC，∠CDA=25°，then m ∠AOB= ．
- As shown in the figure，∠AOB=，so∠ACB= ______；
数学final代考
- If the radius of the base circle of the cone is 2cm, the generatrix is 4cm, the area of the cone side is ( ). 数学final代考
A B. C. D.
9.ABCD is a inscribed quadrilateral of a circle,∠A、∠B、∠C=1∶2∶3，so the biggest angle is_____°
10.As shown in the figure, BD is a diameter of ，∠CBD＝30°，then ∠A=________°.
11.As shown in the figure，AC is diameter of ⊙O，If ∠1=46°，∠2=28°，
then ∠CAB=______°, ∠ACD=______°, ∠DCB=________°.
12.As shown in the figure, △ABC is inscribed ⊙O，AC is a diameter of ⊙O，∠ACB＝500，Point D is on arc ，find m ∠D＝______.
13.As shown in the figure，AB is a diameter of ⊙O，CD is chord of ⊙O，AB=6,
- ∠DCB=30°，find the length of chord BD.
14.In “Pass the exam”, choose a letter randomly，the probability of “a” is . 数学final代考
15.There are 3 balls that are white, yellow and red in a box, they are only different in color, Tom take one out, mark the color then put it back, take one again, calculate the probability with two same colors. .
16.There are 3 different locks and four keys. 3 keys can open the 3 locks respectively, but the forth key cannot open either lock. Taking one key randomly to open either lock, what is the probability that the lock is opened on the first try?
- Every company who participates in the trade fair signed contract with another, and all companies signed 55 contracts in all. How many companies attend the trade fair?
- As shown in the figure, AB is a diameter of ⊙O, chord CD⊥AB, if ∠CDB＝30°，CD＝4，then the area of the shaded part is ( )
数学final代考
A．π B．2π
C.3(2)π D.3(2)π
19As in the picture, if you may switch off any two of switches K1，K2 ，K3， What is the probability that the lights are off? ( )
A.6(1) B. 3(1)
C.2(1) D.3(2)
- One day Grade 7, 8 and 9 students went to have activities. Each Grade students need to select one activity from the following.
- clean the street B. visit the seniors C. have performance in the community
(1) Use a tree diagram to describe all the probabilities. 数学final代考
(2) Find the probability that Grade 9 students have the performance in the community.
