∫ 1 / (the third power of 1 + x) DX how to do ah ah, I used the cubic formula ah But how can we offset it

∫ 1 / (the third power of 1 + x) DX how to do ah ah, I used the cubic formula ah But how can we offset it

∫ 1/(1+x³) dx=∫ 1/[(1+x)(x²-x+1)] dx=(1/3)∫ 1/(x+1) dx - (1/3)∫ (x-2)/(x²-x+1) dx=(1/3)ln|x+1| - (1/6)∫ (2x-1-3)/(x²-x+1) dx=(1/3)ln|x+1| - (1/6)∫ (2x-1)/(x²-x+1) dx + (...

Given a + B = 7, ab = 10, find the value of a cube + B cube

A cube + B cube
=(a+b)(a²-ab+b²)
=(a+b)[(a+b)²-3ab]
=7(7²-30）
=133

According to the thinking of the sixth grade, (1) there are () 6% in 30%. (2) after removing the percentage sign of a percentage, the number () is 100 times. (3) on tree planting day, a school organized students to plant 300 trees, 294 of which survived, with a survival rate of ()%. (4) Master Wang processed 100 parts, 2 of which were unqualified, with a qualified rate of ()%. (5) 12 / () = 0.2 = (): () = () / 20=（ ）%(6) a rope is 8 meters long, cut off 4 meters, cut off the rest of the ()%. Fill in the blanks. Just need the answer, add the serial number in front, or you will be confused

(1) There are (5) 6% in 30%
(2) After removing the percentage sign of a percentage, the result is (expanded) 100 times
(3) On tree planting day, a school organized students to plant 300 trees, of which 294 survived, with a survival rate of (98)%
(4) Master Wang processed 100 parts, 2 of which were unqualified, and the qualified rate was (98)%
（5）12/（60）=0.2=（1）：（5）=（4）/20=（20）%.
(6) A rope is 8 meters long, cut off 4 meters, cut off the remaining (100)%

As shown in the figure, the cross-sectional area of the reservoir dam is trapezoidal, ∠ B = 30 °, C = 45 °, ad = 6m on the dam crest, CD = 20m

Where is the picture?

Cheetah is the champion of sprint among animals. Its speed can reach 100 km / h. how many kilometers can it run per minute at this speed

100 / 60 = 1.67 km

Let n-order matrix a satisfy that a is equal to a, and a is not equal to e. it is proved that the determinant of a is equal to 0
Urgent! Everyone help! There are bonus points!

AA=A => AA-AE=O => A(A-E)=O =>|A|*|A-E|=0
But a ≠ e, so | a | = 0

Put the nine numbers 1, 2, 3, 4, 5, 6, 7, 8, 9 in the box to make the equation hold. How many different ways can you think of? □□□=12×□□□=13×□□□

According to the stem analysis, 327 = 12 × 654 = 13 × 981, or 273 = 12 × 546 = 13819

A is a square matrix of order n, B is an n * s matrix, and the rank r (b) = n. It is proved that (1) AB = 0, then a = 0 (2) AB = B, then a = E

First question
Because AB = 0
So r (a) + R (b)

3 times of 5 is more than half of a number 8. Find this number

Let this number be X
5*3-1/2x=8
1/2x=15-8
1/2x=7
x=14

How many centimeters are the length, width and height of the 16:9 wide screen of a 24 inch TV?

The length is not fixed
Long (square) + wide (square) = 24 inches (square)
24 inches is the length of the diagonal line of the display, which is 24x2.54 in centimeters
Math good students to calculate!