20 12 answers to the top three questions of Shandong mathematics in the college entrance examination. . .

Three. 17, 1: f (x) = m times n= root 3Acosx times sinx+ half a times cos2x=A times sin(2x+6 π).

Meaning from the question: when x takes 6/6 π as the maximum value, substitute x into the above formula to get A=6.

2: Y=6sin(2x+3 π) after left shift, and y=g(x)=6sin(4x+3 π) after shortening.

When x takes 5π of 24, y= 65438+ 0 of minus 2.

When x takes 1 of 24, Y = 1.

Answer: negative two thirds 1, 1.

18, 1: Because AE is perpendicular to BD, we can get that AD is perpendicular to BD by lifting, and we can get the first question.

2. Coordinate system: CF is the z axis, CB is the x axis, and CD is the y axis. Let CB= 1.

Find the normal vector n 1=( 1, 1, 1) of triangles FDB and DBC, and N2 = (0,0, 1).

Press cos

19, 1: p (a) = 3/4 times 1+4 times 1 times 2/3 times 1+4 times 1.

2: (I draw vertically)

X P

0 36 1

1 12 part 1

2 9 1

Two thirds 1

4 9 1

5/3 1

Part 02 of ex = 65438+4 1

I'm so tired. Good luck in the exam!