Senior 1 Mathematics, 2 3 questions, to the specific process

Translate 2 to the right to get y=2cos2(x- 2) y=2cos(2x- )

The abscissa of all points is shortened to 1 2, and y=2cos(4x-) is obtained by the induction formula, and y=-2cos4x is obtained, so d is selected

3.Let (x 2 + 6) = t, that is, y = 4cos (x 2 + 6) = 4cost

When t = 2+k, k z, i.e., (x 2 + 6) = 2+k , k z, (x, y) is the center of symmetry.

x=2 3+2k , k z, (x,y) is the center of symmetry.

Look at the answer again: when k=0, there is a satisfactory answer, so choose b

The image with the function y=2cos2x is shifted to the right by 2 units of length, and then the abscissa of the point of the obtained image is shortened to 1 2 times the original axis, and the ordinate remains unchanged.

The resulting analytic formula is, a y=cos2x b y=-2cosx c y=-2sin4x d y=-2cos4x

1) The image of the function y=2cos2x is translated to the right by 2 unit lengths, and y=2cos[2(x-2)]= 2cos(2x-)= 2cos(-2x)=-2cos2x

2) The abscissa of the point of the obtained image is shortened to 1 2 times the original one, and the ordinate remains unchanged.

t===>t= 2==>w=2 (2)=4 to get y=-2cos4x to choose d

The translation is based on the principle of left addition and right subtraction, so to the right vulture 2 is 2cos2(x-vulture 2)=2cos(2x-vulture)=-2

cos2x abscissa shrinks to the original 1 2, that is, the coefficient becomes 2 times the original, so it is -2cos4x and chooses d

r (r is the independent variable) is symmetrical with respect to r = k vultures + 2 vultures.

So 1 2x + vulture 6=k vulture + vulture 2

When k=0, x is 2 v, 3 choose b

(1): Is there a problem with the question? Is there an x to the fifth power?

2): Solve the proportional number series, the right is, the graph can be known as long as the integer greater than 0 can be (3): from the formula of sn, we can know that the general term formula is (-1) (n-1)*(4n-3) because every two items are added to -4, so you can add -4 to two two, s15=-4*7+n15=-28+57=29, the same way s22=-44 s31=-4*15+n31=61 is added to -76

Next time, can you put brackets with n-1 in (-1) n-1 (4n-3), otherwise the meaning will be completely different......

The first two questions are terrifying.

In the first question, is there a clerical error?

The second question gives an idea.

On the right is a series of proportional numbers, which is simplified to 8[(

Then use mathematical tools to figure out the intersection of the left and right functions.

Write about the third question.

sn = (1-5)+(9-13)+.

Found it, so s22 = (-4)*11 = -44 Note that n must be even.

a15 = 57

s15 = s14 + a15 = (-4)*7 + 57 = 29a31 = 121

s31 = s30 + a31 = (-4)*15 + 121 = 61

s15 + s22 - s31

I'm going to go, why don't you give out 100 points first.

I'm also a freshman in high school, so I want to ask you, you are **, and you feel like you're in the same place.

1 1) Point oblique y-3=x-1; 2)y=1;3)x=-2

2 oblique truncation y=(root number 3 2)x-2

There are no steps to this question.

<> Ru shouted for the map, Zheng quietly destroyed the skin.

One hemisphere, one cone.

'(x) = 3x +1, f according to the question'(x0)=4, and the solution is x0= 1

p(1,0) or p(-1,-4).

f'(x) = 2ax, f according to the title'(1)=2,∴a=1

4/3πr³=4πr²

r=3 for b2The figure is a ball and a box.

Sphere volume = 4 3 (3 2) = 9 2 Box volume = 3 3 2 = 18

So choose B

2 c (x^2-x-6)/(x-1)>0 (x-3)(x+2)(x-1).>0 x>3 -23 a 2asinb = root number 3b 2a root number 3 = b tremor grip sinb a repentance root number 3 2 = b sinb sina = root number 3 2 a = 3

2. When c x 1.

x 2-x-6 0, get x 3 or x answer finch -2 so x 3 when x 1.

x 2-x-6 0, get -2 x 3

So -2 x 1

The overall comic can be obtained with x 3 or -2 x 1

3. A2AsinB= 3B, get Sinb B= 3 2A=sina A, so Sina= 3 2

Then a = 3 or 2 3

But there is only one 3 in the selection that can be satisfied.

So choose A If you still don't understand, please continue to ask.

If you agree with me, please click the [For Satisfaction] button in time.

Hand clearing: Friends who ask questions in the morning can comment on [Satisfied] in the upper right corner of the client.

2.-1/16

Question 2, the idea of going upstairs is no problem, that is, x1+x2=-1, x3+x4=-1;

So his final a+b=-1 16