Simple calculation of 0.125 times 3 / 4 plus 1 / 8 times 8.25 plus 0.125

Simple calculation of 0.125 times 3 / 4 plus 1 / 8 times 8.25 plus 0.125

0.125 times 3 / 4 plus 1 / 8 times 8.25 plus 0.125
=0.125×0.75+0.125×8.25+0.125
=0.125×(0.75+8.25+1)
=0.125×10
=1.25

Why can't Dirichlet function draw function image

Strictly speaking, Dirichlet function has image, but because rational numbers are dense, there is no so-called vacuum zone, but there is a small gap (that is, the position of irrational numbers), so it can not be simply represented by lines. But if you have to draw, you can use some words to explain it,
Draw two straight lines, y = 1, and then note: dig out all the points whose abscissa is irrational
Y = 0, note: dig out all points whose abscissa is rational number

In trapezoidal ABCD, AB / / CD, AC is vertical to BD, angle BDC = 60 degrees, AC = 3 root sign 3, find the length of BD and the area of trapezoidal ABCD
In trapezoid ABCD, AB / / CD, AC is vertical BD, angle BDC = 60 degrees, AC = 3, root 3,
Finding the length of BD and the area of trapezoid ABCD

Make a parallel line of BD through point C, and cross the extension line of AB at point E
Then the quadrilateral DBCE is a parallelogram
∴CE=BD,∠E=∠BDC=60°,∠ACE=90°
∵AC=3√3
∴CE=3
∴BD=3
∵ △ ADC area = △ BCE area (equal base and equal height)
The area of trapezoidal ABCD = △ ace = 1 / 2 * 3 * 3 √ 3 = (9 / 2) √ 3

Example: 17km = 17 times 10 to the third power M = 1.7 times 10 to the fourth power M. Q: 0.0083um=________ m=_____________ m

=0.0083×10^-6 m = 8.3×10^-9 m

If there are 3 pears for each child, there will be 12 more. If there are 5 pears for each child, there will be 6 less. How many children and how many pears are there?

There are x children
3x+12=5x-6
x=9
So there are nine kids, 39 pears

A rectangle has a circumference of 36 cm and a length of 10 cm. How many cm should it be wide?

36 △ 2-10 = 18-10 = 8 (CM) a: the width is 8 cm

How to calculate 1-3 + 5-7 + 9 +. + 2005-2007

1-3=-2
5-7=-2
9-11=-2
……
……
……
2005-2007=-2
So, 1-2007, a total of 1004 odd books, there are 502 groups - 2
So: the answer = - 2 * 502 = - 1004

A train passes through a 5.3 km long tunnel. It takes 7 minutes for the train to enter the tunnel from the front and exit the tunnel from the rear. It is known that the speed of the train is 0.8 km per minute. How long is the train?

Because from the front of the car into the tunnel, the tail out of the tunnel, the distance the train has traveled is the length of the tunnel plus the length of the train, so
Length of train = 7 × 0.8-5.3 = 0.3 (km) = 300 (m)
So this train is 300 meters long

The circumference of a rectangle is 12 cm. Its length is twice its width. What's its area
What does each movie mean?

The ratio of length to width is 2:1, and the sum of length and width is 12 / 2
So: width 12 △ 2 △ 2 + 1 = 2
Length 4
Area 4 × 2 = 8 square centimeter

Given the function f (x) = ln (1 + x) - x, the sequence {an} satisfies A1 = 1 / 2, LN2 + LNA (n + 1) = a (n + 1) + F (a (n + 1) an)
(1) Proving ln (1 + x)

1. By deriving f (x), we get the meaningful value range of X (- 1, positive infinity) for the function whose derivative is 1 / (1 + x) - 1
When x belongs to (- 1,0), it increases (0, positive infinity) and decreases (0, positive infinity), then it has the maximum value at x = 0, which is 0
That is, f (x) > = 0 is ln (1 + x) > = X
two