Given that vector a = (SiNx, 3 / 2), vector b = (cosx, - 1), find (1) if vector a is parallel to B, find Tan (2x Pie / 4) (2) let x belong to (0 Given vector a = (SiNx, 3 / 2), vector b = (cosx, - 1), find (1) if vector a is parallel to B, find Tan (2x Pie / 4) (2) let x belong to (0, Pie / 2), find the minimum value of F (x) = (vector a + b) * B

Given that vector a = (SiNx, 3 / 2), vector b = (cosx, - 1), find (1) if vector a is parallel to B, find Tan (2x Pie / 4) (2) let x belong to (0 Given vector a = (SiNx, 3 / 2), vector b = (cosx, - 1), find (1) if vector a is parallel to B, find Tan (2x Pie / 4) (2) let x belong to (0, Pie / 2), find the minimum value of F (x) = (vector a + b) * B

(1) A parallel B: SiNx / cosx = - 3 / 2 = TaNx
tan2x=12/5
tan(2x-π/4)=(tan2x-1)/(1+tan2x)=7/17
(2)f(x)=(a+b)b=(sinx+cosx,1/2)*(cosx,-1)
f(x)=(√2/2)sin(2x+π/4)
x∈(0,π/2)
When x = π / 2, f (x) has a minimum value of - 1 / 2
Analysis: This is a question about trigonometric function! Nested in the question vector problem! 1. The two vectors are parallel! So the slopes of the two vectors are the same! According to the formula to find out X and then into the evaluation 2, is about simplifying trigonometric function! Let's set up a formula! Finally, according to the graph of trigonometric function, we can know the maximum and minimum! Because the answer with mobile phone only tells you the method! ... unfold
Analysis: This is a question about trigonometric function! Nested in the question vector problem! 1. The two vectors are parallel! So the slopes of the two vectors are the same! According to the formula to find out X and then into the evaluation 2, is about simplifying trigonometric function! Let's set up a formula! Finally, according to the graph of trigonometric function, we can know the maximum and minimum! Because the answer with mobile phone only tells you the method! Put it away
(1) A parallel B, SiNx / cosx = - 3 / 2 = TaNx, tan2x = 12 / 5, Tan (2x - π / 4) = (tan2x-1) / (1 + tan2x) = 7 / 17
(2) When f (x) = (a + b) B = (√ 2 / 2) sin (2x + π / 4) x ∈ (0, π / 2) x = π / 2, f (x) has a minimum value of - 1 / 2
It is proved that the value of sin3x (SiNx) ^ 3 + cos3x (cosx) ^ 3 - (cos2x) ^ 3 is a constant independent of X
sin3xsin^3x+cos3xcos^3-(cos2x)^3=sin2xcosxsin^3x+cos2xsin^4x+cos2xcos^4x-sin2xsinxcos^3x-(cos2x)^3=(1/2)(sin^2(2x)sin^2x-sin^2(2x)cos^2x)+cos2x(sin^4x+cos^4x)-(cos2x)^3=-(1/2)sin^2(2x)cos2x+cos2x(sin^...
The fourth grade of primary school
640÷80= 15×5= 23×3=
12×2×5= 480÷80= 16×5=
27×3= 90÷15= 48÷4=
640÷16= 39÷3= 24×20=
32×3= 48÷16= 12×8=
27×3= 56÷14= 24÷8=
14×2= 83－45= 560÷80=
96÷24= 40÷20= 40×30=
37＋26= 76－39= 605＋59=
30×23= 12×8= 27＋32=
48＋27= 4500×20= 73＋15 =
120×600 = 200×360= 6800×400=
280＋270= 4×2500= 6000÷40=
5×1280= 310－70= 400×14=
470＋180= 1000÷25= 160×600=
20×420= 290×300= 8100÷300=
7600÷200= 7600÷400= 680＋270=
980÷14= 4200÷30= 6×1300=
1300×50= 200×48= 930－660=
530＋280= 9200÷400= 840÷21=
180×500= 8000÷500 = 1900÷20=
200×160= 8700÷300= 300×330=
3×1400= 7000÷14= 600÷12=
9600÷80= 140×300= 8800÷40=
9600÷800= 750－290= 5×490=
760×20= 7500÷500= 370×200=
650÷13= 8600－4200= 240×4=
640÷80= 15×10= 12×11=
160×30= 220×40= 104×5=
4500÷50= 20×2= 90÷30=
270÷30= 270×30= 84÷21=
76÷9= 66÷7= 100－54=
23＋15= 360÷4= 55÷5=
32×6= 7000÷70＝ 200÷40＝
180÷30= 240÷40= 35×2=
140×7= 13×6= 280×3=
350×2= 50×11= 250×6=
7200+900= 410-201= 125×8=
48×20= 6600÷600= 390+140=
11×80= 24×50= 3600÷400=
4000÷50= 530－70= 420－90=
9600÷30= 7×700= 203+98=
1800÷300= 240+570= 4800÷400=
370+580= 580－490= 910－370=
420－90＝ 170＋320＝ 1000－51＝
520－260＝ 910－190＝ 35×200＝
22×200＝ 8800÷400＝ 9300÷300＝
6×300＝ 1800÷200＝
It's disgusting to buy a mental arithmetic book
Just buy a mental arithmetic card
60×11=660 100×24=2400 24×4=96 16×4=64 75×3=225 25×2=50 2×310=620
70×13=910 21×60=1260 55×2=110 450×3=1350 360×5=1800 48×7336=353568 34×3=102
20 × 45 = 900 60 × 90 = 5400 8 × 105 = 840 50 × 70 = 350
60×11=660 100×24=2400 24×4=96 16×4=64 75×3=225 25×2=50 2×310=620
70×13=910 21×60=1260 55×2=110 450×3=1350 360×5=1800 48×7336=353568 34×3=102
20×45=900 60×90=5400 8×105=840 50×70=3500 18×5=40 350×4=1400 500×5=2500
30×12= 23×4= 540-310= 4×140= 630+70= 130×20= 180×5=　15×5= 23×3=
170 × 5 = 500 × 5 = 85 × 40 = 25 × 4 = 31 × 30 = 12 × 8 = 96 32 × 3 = 456 × 33 = Stow
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9600÷80= 140×300= 8800÷40=
9600÷800= 750－290= 5×490=
760×20= 7500÷500= 370×200=
650÷13= 8600－4200= 240×4=
The mixed operation of rational numbers in the first grade of junior high school mathematics, word disorder, make do, score is still high, I want process, speed, score is high
It is known that the quadratic power of (A's first power - 1) + the quadratic power of | a - 2 | + (A's third power - 3) + the quadratic power of | A's fourth power - 4 | + +(A's power 2009-2009) quadratic + | A's power 2010-2010 | = 0, find 1 / A's first power × A's second power + 1 / A's second power × A's third power + 1 / A's third power × A's fourth power + +1 / A to the power of 2009 × a to the power of 2010
How many
You're kidding. It's not right
It's not that you're confused
It's not right at all
A is a rational number and cannot be satisfied
The second power of (a) - 1 + the second power of (a) - 2 + (a) - 3 + the fourth power of (a) - 4 + +The second power of (A's power of 2009-2009) + | A's power of 2010-2010 | = 0
The latter is even more outrageous. Why bother to ask for 2009a
You're kidding. It's not right
It's not that you're confused
It's not right at all
A is a rational number and cannot be satisfied
The second power of (a) - 1 + the second power of (a) - 2 + (a) - 3 + the fourth power of (a) - 4 + +The second power of (A's power of 2009-2009) + | A's power of 2010-2010 | = 0
The latter is even more outrageous. I'm not asking for 2009a directly. Why bother to put it away
2009/2010
If the sequence {an} is an arithmetic sequence with non-zero tolerance, and A1, A3 and A7 are three consecutive terms of the arithmetic sequence {BN}, then
Then the common ratio Q of {BN} is?
Let the tolerance be d
a3=a1+2d,a7=a1+7d
a3/a1=a7/a3
(a1+2d)/a1=(a1+6d)/(a1+2d)
The results show that A1 = 2D
q=a3/a1=(a1+2d)/a1=(2d+2d)/2d=2
What's the problem?
What are the four derivative algorithms?
(u+v)'=u'+v'
(u-v)'=u'-v'
(uv)'=u'v+uv'
(u/v)'=(u'v-uv')/v^2
If you can't deduce this kind of thing, just look up the textbook
How to reduce the error of decimal addition and subtraction
Unit 4 decimal addition and subtraction, grade 5, primary school mathematics, focuses on learning the vertical calculation of decimal addition and subtraction. In teaching this part of the content, as long as we emphasize writing the vertical, pay attention to the decimal point alignment, that is, make the digits aligned, so that the numbers on the same digits can be added and subtracted. I believe that most students can calculate the positive
The mixed operation of rational numbers (1) the answer of expansion and extension
It's volume one, published by Su Jiao
Expansion and extension
3, find (- 1 and 3 / 4-7 / 8)
=130 out of 33
4, if / ab-2 / and
=2013 / 2014
What does it mean
The sequence {an} is an arithmetic sequence with non-zero tolerance, and A1, A3 and A7 are three consecutive terms of the arithmetic sequence {BN}. If B1 = 1, then b2005=______ .
In the arithmetic sequence {an}, A1 = B1 = 1, A3 = 1 + 2D, a7 = 1 + 6D, because A1, A3, a7 are just the first three consecutive terms of some arithmetic sequence {BN}, so there is A32 = a1a7, that is, (1 + 2D) 2 = 1 × (1 + 6D), and the solution is d = 12, (d = 0 rounding off), so the general term formula of B1 = 1, B2 = A3 = 2, B3 = A7 = 4 arithmetic sequence {BN} is: BN = 2N-1, so b2005 = 22004
Do you have four arithmetic problems in grade six
More decimals and less fractions
1. 3/7 × 49/9 - 4/3
2. 8/9 × 15/36 + 1/27
3. 12× 5/6 – 2/9 ×3
4. 8× 5/4 + 1/4
5. 6÷ 3/8 – 3/8 ÷6
6. 4/7 × 5/9 + 3/7 × 5/9
7. 5/2 -（ 3/2 + 4/5 ）
8. 7/8 + （ 1/8 + 1/9 ）
9. 9 × 5/6 + 5/6
10. 3/4 × 8/9 - 1/3
11. 7 × 5/49 + 3/14
12. 6 ×（ 1/2 + 2/3 ）
13. 8 × 4/5 + 8 × 11/5
14. 31 × 5/6 – 5/6
15. 9/7 - （ 2/7 – 10/21 ）
16. 5/9 × 18 – 14 × 2/7
17. 4/5 × 25/16 + 2/3 × 3/4
18. 14 × 8/7 – 5/6 × 12/15
19. 17/32 – 3/4 × 9/24
20. 3 × 2/9 + 1/3
21. 5/7 × 3/25 + 3/7
22. 3/14 ×× 2/3 + 1/6
23. 1/5 × 2/3 + 5/6
24. 9/22 + 1/11 ÷ 1/2
25. 5/3 × 11/5 + 4/3
26. 45 × 2/3 + 1/3 × 15
27. 7/19 + 12/19 × 5/6
28. 1/4 + 3/4 ÷ 2/3
29. 8/7 × 21/16 + 1/2
30. 101 × 1/5 – 1/5 × 21
31.50＋160÷40 （58+370）÷（64-45）
32.120-144÷18+35
33.347+45×2-4160÷52
34（58+37）÷（64-9×5）
35.95÷（64-45）
36.178-145÷5×6+42 420+580-64×21÷28
37.812-700÷（9+31×11） （136+64）×（65-345÷23）
38.85+14×（14+208÷26）
39.（284+16）×（512-8208÷18）
40.120-36×4÷18+35
41.（58+37）÷（64-9×5）
42.(6.8-6.8×0.55)÷8.5
43.0.12× 4.8÷0.12×4.8
44.（3.2×1.5+2.5）÷1.6 （2）3.2×（1.5+2.5）÷1.6
45.6-1.6÷4= 5.38+7.85-5.37=
46.7.2÷0.8-1.2×5= 6-1.19×3-0.43=
47.6.5×（4.8-1.2×4）= 0.68×1.9+0.32×1.9
48.10.15-10.75×0.4-5.7
49.5.8×（3.87-0.13）+4.2×3.74
50.32.52-（6+9.728÷3.2）×2.5
51.[（7.1-5.6）×0.9-1.15] ÷2.5
52.5.4÷[2.6×（3.7-2.9）+0.62]
53.12×6÷（12-7.2）-6 （4）12×6÷7.2-6
1. 3/7 × 49/9 - 4/3
2. 8/9 × 15/36 + 1/27
3. 12× 5/6 – 2/9 ×3
4. 8× 5/4 + 1/4
5. 6÷ 3/8 – 3/8 ÷6
6. 4/7 × 5/9 + 3/7 × 5/9
7. 5/2 -（ 3/2 + 4/5 ）
8. 7/8 + （ 1/8 + 1/9 ）
9. 9 × 5/6 + 5/6
10. 3/4 × 8/9 - 1/3
11. 7 × 5/49 + 3/14
12. 6 ×（ 1/2 + 2/3 ）
13. 8 × 4/5 + 8 × 11/5
14. 31 × 5/6 – 5/6
15. 9/7 - （ 2/7 – 10/21 ）
16. 5/9 × 18 – 14 × 2/7
17. 4/5 × 25/16 + 2/3 × 3/4
18. 14 × 8/7 – 5/6 × 12/15
19. 17/32 – 3/4 × 9/24
20. 3 × 2/9 + 1/3
21. 5/7 × 3/25 + 3/7
22. 3/14 ×× 2/3 + 1/6
23. 1/5 × 2/3 + 5/6
24. 9/22 + 1/11 ÷ 1/2
25. 5/3 × 11/5 + 4/3
26. 45 × 2/3 + 1/3 × 15
27. 7/19 + 12/19 × 5/6
28. 1/4 + 3/4 ÷ 2/3
29. 8/7 × 21/16 + 1/2
30. 101 × 1/5 – 1/5 × 21
31.50＋160÷40 （58+370）÷（64-45）
32.120-144÷18+35
33.347+45×2-4160÷52
34（58+37）÷（64-9×5）
35.95÷（64-45）
36.178-145÷5×6+42 420+580-64×21÷28
37.812-700÷（9+31×11） （136+64）×（65-345÷23）
38.85+14×（14+208÷26）
39.（284+16）×（512-8208÷18）
40.120-36×4÷18+35
41.（58+37）÷（64-9×5）
42.(6.8-6.8×0.55)÷8.5
43.0.12× 4.8÷0.12×4.8
44.（3.2×1.5+2.5）÷1.6 （2）3.2×（1.5+2.5）÷1.6
45.6-1.6÷4= 5.38+7.85-5.37=
46.7.2÷0.8-1.2×5= 6-1.19×3-0.43=
47.6.5×（4.8-1.2×4）= 0.68×1.9+0.32×1.9
48.10.15-10.75×0.4-5.7
49.5.8×（3.87-0.13）+4.2×3.74
50.32.52-（6+9.728÷3.2）×2.5
51.[（7.1-5.6）×0.9-1.15] ÷2.5
52.5.4÷[2.6×（3.7-2.9）+0.62]
53.12×6÷（12-7.2）-6 （4）12×6÷7.2-6
1. 3/7 × 49/9 - 4/3
2. 8/9 × 15/36 + 1/27
3. 12× 5/6 – 2/9 ×3
4. 8× 5/4 + 1/4
5. 6÷ 3/8 –