(x + 1) (x + 1) - (x-1) (1-x) = 6 find the solution of X (X-2) (2x + 1) = (2x + 1) (x + 1) solve the equation by factorization

(x + 1) (x + 1) - (x-1) (1-x) = 6 find the solution of X (X-2) (2x + 1) = (2x + 1) (x + 1) solve the equation by factorization

(x+1)(x+1)-(x-1)(1-x)=6
(x+1)^2 +(x-1)^2 = 6
2x^2+2 = 6
x^2=2
x1=-√2,x2=√2
（x-2)（2x+1）=(2x+1)(x+1)
（x-2)（2x+1）-(2x+1)(x+1) = 0
（2x+1）(x-2-x-1) = 0
（2x+1）(-3) = 0
2x+1=0
x=-1/2

(2x + 3) & sup2; = 2x + 3 to solve quadratic equation with one variable,

(2x+3)²-(2x+3)=0
(2x+3)[(2x+3)-1]=0
2(2x+3)(x+1)=0
x=-3/2,x=-1

The minimum value is obtained by means of the mean value theorem,

0

F (x) is a piecewise function, f (x) = SiNx / X (x ≠ 0), f (x) = 1 (x = 0) find F "(0)
On the second floor, there seems to be a problem in your solution of F '(x), f' (x) = (xcosx SiNx) / x ^ 2, so Then I got confused. Thank you for your answers. In the process of implementation, how to find the limit of sin (x) / x ^ 3. If the final problem is solved, then the problem will be solved.

I think this problem should be solved from the definition of derivative as follows: F '(0) = LIM (f (x) - f (0)) / x) = 0 (X -- > 0) when x = 0 is continuous for f' (x), we get a new piecewise function f '(x) = (sinx-xcosx) / x ^ 2, X does not = 0 = 0, x = 0, discuss the case of F' '(x) derivative at x = 0, f' '(0)

The volume of a large square is 27 cubic centimeters. Now divide it into eight small squares. How many centimeters is the edge length of the small cube?

27 = 3 × 3 × 3 indicates that the edge length of the large cube is 3cm, 8 = 2 × 2 × 2 indicates that there are two small cubes on each edge after segmentation,
3÷2=1.5cm

On the determination of congruence of triangles
The number of triangles that can be formed by connecting the ends of the sticks with the lengths of 3cm, 4cm and 5cm is ()
A.1 B.2 C.3 D.0
Thank you very much for not understanding

A
The so-called difference refers to different shapes, and the hook three strands four Xuan five is already a definite right triangle, so it can only form a triangle

How to find the second derivative of the derivative dy / DX of the parametric equation x = a (t-sint) y = a (1-cost)?

Obviously
dx/dt=a(1-cost)
dy/dt=a*sint
that
dy/dx=sint /(1-cost)
If we continue to seek the second derivative, we will get the result
d(dy/dx)/dt *dt/dx
=[(sint)' *(1-cost) -sint *(1-cost)']/(1-cost)^2 *1/ a(1-cost)
=(cost-1)/(1-cost)^2 *1/ a(1-cost)
= -1/ [a(1-cost)^2]

How many squares are there in a big square made up of 16 small squares

There are 4x4 = 16 with one edge,
There are 3x3 = 9 edges with two lattices
There are 2x2 = 4 edges with 3 lattices
There is only one with four sides, 16 + 9 + 4 + 1 = 30

There are four big pillars in the corridor of the gymnasium. The perimeter of the bottom surface of each pillar is 3.14 meters, and the height is 10 meters. These pillars need to be repainted. The area of painting
How much is it

3.14 × 10 × 4 = 125.6 (M2)

666 = 1999 how to add operation symbols and brackets in the middle of numbers to make the formula hold
2 = 1999 how to add operation symbol and bracket in the middle of the number to make the formula hold
8 8 8 8 8 8 8 8 8 8 8=1999

2222-222-22/22=1999
666+666+666+6/6=1999
8888/8+888+(8-8)/8=1999