On the freeway, if a car with a length of 4 meters and a speed of 110 km / h is ready to overtake a truck with a length of 12 meters and a speed of 100 km / h, it will take about () A. 1.6 seconds B. 4.32 seconds C. 5.76 seconds D. 345.6 seconds

Suppose that the required time is x seconds, 110 km / h = 2759 M / s, 100 km / h = 2509 M / s. according to the distance that the car takes is equal to the distance that the truck takes plus the body length of the two cars, the solution is: 2759x − 2509x = 12 + 4, x = 5.76, so choose C

Xiao Wang rowed at a speed of 12 km / h in still water. Now he went back and forth to a river. It took 10 h to go upstream and 6 h to go downstream. The water velocity of the river was calculated
Please tell me the method,

Set water speed x km
（12+x）6=（12-x)10
72+6x=120-10x
16x=48
x=3
A: the water speed is 3 km
If you can,

0, 64 × 14 =? 3, 8 × 24 =? 11, 4 × 19 =? 5, 6 × 1, 8 =?

896

Given that the function f (x) is differentiable on [0,1], satisfying XF '(x) = f (x) + 3x & # 178;, we try to find f (x) so that the volume of the body of revolution is the smallest when the plane figure surrounded by the curve y = f (x) and the straight lines X = 0, x = 1 and y = 0 rotates around the X axis

As a result of the integral of: F (x) (x) (x (x) (x) (x (x) (f (x) (f (x) (x) (f (x) (x) (f (x) (f (x) (x) (x-f (x) (x) (x-f (x) (x) (x-f (x) (x) (x) (x-f (x) (x) (x-f (x) (x) (x-f (x) (f (x) (x) (x) (f (x) (x) (f (x) (x-f (x) (x) (x)) (x (x) (x) (x (x) (x (x (x (x (x) (x) (x) (x) DXX) DX = (0 → 1) \8747\\\\\8747\\\\8747\\\\\\inthis paper, we present a method to solve this problem

If X & # 178; - 4x + Y & # 178; + 8y + 20 = 0, find the value of X, y

x²-4x+y²+8y+20=0
(x-2)²+(y+4)²=0
x-2=0
y+4=0
x=2
y=-4

Find the sum of the first n terms of the sequence {(2n-1) * 3 ^ n}

Subtract by dislocation: SN = 1 * 3 ^ 1 + 3 * 3 ^ 2 + 5 * 3 ^ 3 +. + (2n-1) * 3 ^ N3 * Sn = 1 * 3 ^ 2 + 3 * 3 ^ 3 +. + (2n-3) * 3 ^ n + (2n-1) * 3 ^ (n + 1) - 2Sn = 1 * 3 ^ 1 + 2 * 3 ^ 2 + 2 * 3 ^ 3 +. + 2 * 3 ^ n - (2n-1) * 3 ^ (n + 1) = 3 + 2 * (3 ^ 2 + 3 +. + 3 ^ n) - (2n-1) * 3 ^ (n + 1) = 3-9 + 3 ^ (n + 1) - (2n-1) * 3 ^ (n + 1)

What is the difference between logarithm and exponent

Logarithm operation and direct operation are inverse operations. Exponential operation is to find power with known base and exponent. Logarithm operation is to find power with known base and exponent

Input two positive integers m and N, find the greatest common divisor and least common multiple. Java must be used to do

import java.util.Scanner ;
public class TestNum {
public static void main(String[] args) {
Scanner sca =new Scanner( System.in );
System.out.println ("please enter two numbers:); / / enter two numbers separated by spaces
int m = sca.nextInt ();
int n = sca.nextInt ();
int temp,r;
if(n

What is the sentence in Three Gorges describing the scenery of spring and winter in summer

Spring and winter, then / plain turbulence / green pool, back to the clear / reflection. Jue Yao / many strange cypresses, hanging spring waterfall, flying among them. Qing / Rong / Jun / Mao, a lot of fun

On the freeway, if a car with a length of 4 meters and a speed of 110 km / h is ready to overtake a truck with a length of 12 meters and a speed of 100 km / h, it will take about () A. 1.6 seconds B. 4.32 seconds C. 5.76 seconds D. 345.6 seconds