The minimum value of function y = 1-2 The minimum value of the function y = 1, X2 - 2, x + 6 is__________ The first two is the quadratic velocity of X

The minimum value of function y = 1-2 The minimum value of the function y = 1, X2 - 2, x + 6 is__________ The first two is the quadratic velocity of X

Analysis: y = 1 / x ^ 2-2 / x + 6 = (1 / x-1) ^ 2-1 + 6 = (1 / x-1) ^ 2 + 5 ≥ 5

Given that the function f (x) = - x + log is 1-x / 1 + x power of 2, find f (- 1 / 2007) + F (- 1 / 2008) + F (1 / 2007) + F (1 / 2008) =?
fast

The answer is 0
For the convenience of writing, replace the function with base 2 with base 10, then the original function is changed to:
f（x）=-x+lg[(1-x)/(1+x)]/lg2
Solution 1
From F (x) = - x + LG [(1-x) / (1 + x)] / LG2, it is obtained that:
f（-x）=x+lg[(1+x)/(1-x)]/lg2=-[-x+lg[(1-x)/(1+x)]/lg2]=-f（x)
That is, f (- x) = - f (x), so f (x) is an odd function
So f (- 1 / 2007) = - f (1 / 2007); f (- 1 / 2008) = - f (1 / 2008)
So f (- 1 / 2007) + F (- 1 / 2008) + F (1 / 2007) + F (1 / 2008) = 0
Solution 2
The original formula is further reduced to f (x) = - x + LG [(1-x) / (1 + x)] / LG2
=-x+lg（1-x)/lg2-lg（1+x)/lg2
So f (- 1 / 2007) = 1 / 2007 + LG (1 + 1 / 2007) / LG2 LG (1-1 / 2007) / LG2
=1/2007+lg（2008/2007）/lg2-lg（2006/2007）/lg2
f（-1/2008）=1/2008+lg（1+1/2008)/lg2-lg（1-1/2008)/lg2
=1/2008+lg（2009/2008）/lg2-lg（2007/2008）/lg2
f（1/2007）=-1/2007+lg（1-1/2007)/lg2-lg（1+1/2007)/lg2
=-1/2007+lg（2006/2007）/lg2-lg（2008/2007）/lg2
f（1/2008）=-1/2008+lg（1-1/2008)/lg2-lg（1+1/2008)/lg2
=-1/2008+lg（2007/2008）/lg2-lg（2009/2008）/lg2
So: F (- 1 / 2007) + F (1 / 2007) = 1 / 2007 + LG (2008 / 2007) / LG2 LG (2006 / 2007) / lg2-1 / 2007 + LG (2006 / 2007) / LG2 LG (2008 / 2007) / LG2 = 0
f（-1/2008）+f（1/2008）=1/2008+lg（2009/2008）/lg2-lg（2007/2008）/lg21/2008+lg（2007/2008）/lg2-lg（2009/2008）/lg2=0
So f (- 1 / 2007) + F (- 1 / 2008) + F (1 / 2007) + F (1 / 2008) = 0

If f (1) = 2, then f (2) / F (1) + F (3) / F (2) + f(2008)/f(2007)=?

f(x+1)=f(x)f(1)=2f(x)
f(x+1)/f(x)=2
f(2)/f(1)+f(3)/f(2)+… f(2008)/f(2007)
=2+2+2+...+2
=2*2007
=4014

As shown in the figure, it is known that s is a point out of the plane of the parallelogram ABCD, m and N are points on SA and BD respectively, and SMMA = bnnd. Then the line Mn______ Plane SBC

It is proved that bnnd = bgag can be obtained by making ng ∥ ad through N, intersecting AB with G and connecting mg. According to the known condition bnnd = SMMA, SMMA = bgag, ∥ mg ∥ sb. ∩ mg ⊄ plane SBC, sb ⊂ plane SBC, ⊂ mg ∥ plane SBC. Ad ∥ BC, ∥ ng ∥ BC, ng ⊄ plane SBC, BC ⊂ plane SBC ∩ plane SBC ∩ plane MNG, ⊂ plane MNG, ∥ plane SBC The answer is ‖

If the perimeter of the sector is 50cm and the radius is 12cm, then the area of the sector is______ cm2．

L + 12 × 2 = 50, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; L = 26, n π R180 = 26, n π = 390, n π × 122360, = 390 × 144360, = 156 (square centimeter); a: the area of this sector is 156 square centimeter

Given that the second, third and sixth terms of an arithmetic sequence with nonzero tolerance are three consecutive terms of an arithmetic sequence, then the common ratio of the arithmetic sequence is equal to ()
A. 34B. −13C. 13D. 3

∵ the second, third, and sixth items of the arithmetic sequence with non-zero tolerance are three consecutive items of an arithmetic sequence in turn, ∵ (a1 + 2D) 2 = (a1 + D) (a1 + 5d). After sorting out, we get A1 & nbsp; = − D2. ∵ the common ratio of this arithmetic sequence is q = a1 + 2da1 + D = − D2 + 2D − D2 + D = 3

Tips: there are many small troubles in life. Give full play to them and write a short passage of about 80 words
(.): for example, when you go shopping, the waiter's attitude is not good; when you study, your classmates talk and laugh loudly, etc?

Life is full of trifles, which drives you made. For example, when you go shopping, the waters always follow you, which makes you cannot enjoy yourself. When you want to study something, there are always someone talking about you. Practically, you cannot avoid from these trifles. what should we do? all we should do are to change our attitude and go on to do what we should do .

It is known that the line y = x + 6 intersects the x-axis and y-axis at two points a and B, the line L intersects the line AB at point C through the origin, and the area of △ AOB is divided into two parts of 2:1
Find the analytic expression of the straight line L

Y = x + 6 intersects with X axis and Y axis at two points a and B
Let y = 0, then x = - 6; let x = 0, then y = 6
So the coordinates of a and B are a (- 6,0) and B (0,6) respectively
If the line L passes through the origin and intersects with the line AB at point C, and the area of △ AOB is divided into two parts of 2:1, then s △ AOC = 2S △ BOC, or s △ BOC = 2S △ AOC
Point C is between AB, XA < XC < XB, that is - 6 < XC < 0
If AC is regarded as the base of △ AOC and BC as the base of △ BOC, the height h of the two triangles is equal (both equal to the distance from the origin to ab)
∵S△AOC=1/2AC*h,S△BOC=1/2BC*h
Ψ AC = 2BC, or BC = 2Ac, that is, AC / BC = 2, or AC / BC = 1 / 2
If CE is perpendicular to e and CF ⊥ y is perpendicular to F, then △ ace ∽ CBF
AC / BC = AE / CF = | XC Xa | / | XB XC | = [XC - (- 6)] / (0-xc) = - (XC + 6) / XC = 2, or 1 / 2
-(XC + 6) = 2XC, or - (XC + 6) = 1 / 2XC
-6 = 3xc, or - 6 = 3 / 2XC
XC = - 2, or XC = - 4
YC = XC + 6 = 4, or 2
So the coordinates of point C (- 2,4), or (- 4,2)
The slope of the line passing through the origin and C is k = 4 / (- 2) = - 2, or K = 2 / (- 4) = - 1 / 2
The analytic expression of line L is y = - 2x, or y = - 1 / 2x

The bottom area of a cuboid is 24 square centimeters. The perimeter of the bottom is 20 centimeters. The height is 7 centimeters. What is the surface area of the cuboid? Write it in arithmetic
The simpler the better

It can be seen from the bottom area that the length and width of a cuboid may have these pairs: 8 cm and 3 cm, 6 cm and 4 cm, 12 cm and 2 cm, 24 cm and 1 cm. According to the bottom perimeter of 20 cm, its length and width should be 6 cm and 4 cm. In this way, the surface area of the cuboid can be obtained. The calculation process is as follows:
4 * 6 = 24 (cm2) (4 + 6) = 20 (CM)
(24 + 4 * 7 + 6 * 7) * 2 = 188 (cm2)

Given sin (a-pai / 4) = 7 √ 2 / 10, cos2a = 7 / 25, then the value of Tan (a + Pai / 3) is?

sin(a-pai/4)= √2 *sina/2 -√2cosa/2 =7*√2/10
So Sina - cosa = 7 / 5
In addition, cos2a = cosa * cosa - Sina * Sina
=（cosa- sina）*（cosa+sina）
= 7/25
When Sina - cosa = 7 / 5 is brought in, Sina + cosa = - 1 / 5 is obtained
So from the above two formulas, Sina = 3 / 5, cosa = - 4 / 5
So Tana = - 3 / 4
tan（a+pai/3) = ( tana + tan(pai/3) ) / ( 1 - tana*tan(pai/3) )
Then Tana = - 3 / 4 and Tan (PAI / 3) = √ 3 are taken into the calculation to get the answer
PS: it's hard to write the result, so I'm just lazy here