We know that the function f (x) = 2x ^ 2 + x-k, G (x) = ax ^ 3 + BX ^ 2 + CX + D (a is not equal to 0) is an odd function on R. when x = 1, G (x) obtains the extremum - 2 (1) finds the monotone interval and the maximum of the function; (2) if f (x) is less than or equal to (x) for any closed interval from - 1 to 3, finds the range of real number K 2) If f (x) is less than or equal to G (x) for any closed interval where x belongs to - 1 to 3, find the range of real number K

We know that the function f (x) = 2x ^ 2 + x-k, G (x) = ax ^ 3 + BX ^ 2 + CX + D (a is not equal to 0) is an odd function on R. when x = 1, G (x) obtains the extremum - 2 (1) finds the monotone interval and the maximum of the function; (2) if f (x) is less than or equal to (x) for any closed interval from - 1 to 3, finds the range of real number K 2) If f (x) is less than or equal to G (x) for any closed interval where x belongs to - 1 to 3, find the range of real number K

(1) Because it is an odd function, one extreme point is (1, - 2), and the other extreme point must be (- 1,2),
So in (- 1,1) is decreasing, in (- infinity, - 1), (1, positive infinity) is increasing, maximum = 2
(2) There is a problem in the title

Given the function f (x) = (3x + 2) / (x + 2), (1) if the sequence {an}, {BN} satisfies A1 = 1 / 2, a (n + 1) ＜ note: subscript ＞ f = (an)
The function f (x) = (3x + 2) / (x + 2) is known,
(1) If the sequence {an}, {BN} satisfies A1 = 1 / 2, a (n + 1) ＜ note: subscript ＞ f = (an), BN = 1 / (an + 1) (n ≥ 1), the general term formula of sequence {BN}
(2) Let Sn = B1 + B2 + +BN, if 1 / Sn ≤ m, the minimum value of M is obtained

(1)b1=1/(a1+1)=1/(1/2+1)=2/3b(n+1)=1/(f(an)+1)=(an+2)/(4an+4)=1/4(1+1/(an+1))=1/4(1+bn)==>bn=1/4+1/4b(n-1)=1/4+1/16+1/16b(n-2)=1/4+1/16+1/64+1/64b(n-3)=.=1/4+(1/4)^2+(1/4)^3+...+(1/4)^(n-1)+(1/4)^(n-1...

It is known that the function satisfies f (x) = x / 2, the sequence {an} satisfies the relation an = f [a (n-1)] (n ≥ 2 and N ∈ n), and A1 = 16
(1) Verification: sequence (an) is equal ratio sequence
(2) Finding the general term formula of sequence {an}

an=f[a(n-1)]=a(n-1)/2
An / a (n-1) = 1 / 2, n ≥ 2 and N ∈ n
The sequence (an) is an equal ratio sequence
an=16×0.5^(n－1)

The total resistance of two same resistors in parallel is 5 ohm, and the total resistance of them in series

20 euro

Multiple characteristics of 1,2,3,4,5,6,7,8,9,0

1) If the last digit of an integer is 0, 2, 4, 6 or 8, then the number can be divided by 2. (2) if the sum of numbers of an integer can be divided by 3, then the integer can be divided by 3. (3) if the last two digits of an integer can be divided by 4, then the number can be divided by 4. (4) if the last digit of an integer is 0 or 5, then the number

How does a certain voltage and a certain current increase the brightness
Given the given conditions, the power supply voltage and the light bulb are fixed. How to increase the current to change the brightness? For example, a 12V motorcycle battery is used as the power supply, and three 3V, 350mA light bulbs are connected in series first, and then directly connected to the power supply. How to increase the current and increase the brightness?

One is to increase the number of lamps, the other is to change a high power bulb, the best rated voltage is higher, about 12V
Series connection is very unreliable. After all, there is difference in bulb resistance

The parabola y = 4 / 9x & # 178; - 8 / 3x-12 intersects the x-axis at two points a and C, and intersects the y-axis at point B (1) to calculate the circumscribed circle area of △ AOB (2) if the moving point P starts from point a and moves along the direction of ray AC by 2 units per second; at the same time, point Q starts from point B and moves along the direction of ray Ba by 1 unit per second, when point P reaches point C, the two points stop moving at the same time, A triangle with Apq as its vertex is similar to △ OAB. (3) if M is a moving point on the line AB, passing through the point m and making Mn parallel to the y-axis, it is called a parabola at the point n. ① is there such a point m, so that the quadrilateral omnb is exactly a parallelogram? If there is, find out the coordinates of the point M. if not, explain the reason. ② when the point m moves to where, The area of quadrilateral CBNA is the largest? The coordinates of point m and the area of quadrilateral CBNA are calculated

There is an ammeter with internal resistance Rg equal to 10 ohm and full bias current Ig equal to 3 Ma. How large a partial resistance should be connected in series to refit it into a voltmeter with measuring range of 3 V

Question mark 1: total resistance of series current = sum of resistance of each part
Then we use r total = u / I = 6V / 3mA = 2000 Ω and then use r total - R (g) = R total - 120 Ω = 1880 Ω to get the result
Question mark 2: total current of parallel voltage = sum of current of each part
Then u = I * r = 0.003a * 120 = 0.36v, then r = u / I = 0.36 / (3-0.003) = 0.12 Ω

X * 7 / 4 * 5 / 9 = 21 / 20

x*(4/7)*(9/5)=20/21
x=(20/21)*(7/4)*(5/9)
x=25/27

The influence of soil resistivity on the earth resistance,

For details, please refer to GB / T 2005 edition of technical code for lightning protection
Generally speaking, it is in direct proportion. The soil quality and humidity affect the soil resistivity, and then affect the grounding resistance. The overall direct proportion is too complicated. You can check the specification