All kinds of advanced mathematics are given extra points for correct answers, and correct answers to

1. Yes, but it is also very simple to judge the continuity of functions, and elementary functions are continuous within their defined domains. The elementary combinations of elementary functions (compounds, polynomials, etc.) are also continuous.

Obviously, this method is complex, error-prone, and undesirable, and it is better to use a combination of analytical and geometric methods, which are simple and straightforward.

Left = [0,x] (2t 2+2t|t|) dt

t>=0, t|t| dt= ∫ t^2 dt= t^3/3 + c = |t|t 2 3 + c, t < 0, t|t| dt = -∫t^2 dt = -t^3/3 + c = |t| t^2 / 3 + c

So the original formula = (2t 3 3 + 2|t| t^2 / 3) |0,x] = (2t^2/3 * t + t|))0,x] = 2x^2/3 * x+|x|)

a,b] f(t) f'(t) dt = [a,b] f(t) df(t) = (partial integral) = (f(t) *f(t)) a,b] -a,b] f(t) df(t).

So 2 [a,b] f(t) df(t) = (f(b)) 2 - f(a)) 2, so left = [(f(b)) 2 - f(a)) 2] 2

Let x 2+1=2 get: x= 1, and let x 2+x=2 get: x=1 or x=-2

Note that x 2+x is not always greater than 0, so that x 2+x = 0 gives x = 0 or x = -1

So s= [-2,-1] (x 2+x) dx + 0,1] (x 2+x) dx - 1,0] (x 2+x) dx - 2 * 2 - 1,1] (x 2+1) dx).

Because"x+3 in absolute terms"+"The absolute value of 3y-4"=0, this formula is the addition of two absolute values, and because the absolute value "=0,"."x+3 in absolute terms"with"The absolute value of 3y-4"There will be no negative numbers, and they add up to 0, so"x+3 in absolute terms"with"The absolute value of 3y-4"Both must be equal to 0 in order for the addition to be equal to 0

So the absolute value of x+3 = 0, then x+3=0, the absolute value of x=-33y-4 = 0, then 3y-4=0, y=4 3 so y*y-x = (4 3)*(4 3)-(3) = 43 9, that is, 43/9

The absolute value is greater than or equal to 0

The addition is equal to 0, if one is greater than 0, the other is less than 0, which is not true.

So both are equal to 0

So x+3=0, 3y-4=0

x=-3,y=4/3

So y -x=(4 3) -3)=16 9+3=43 9

Because the absolute value of x+3 + the absolute value of 3y-4 = 0

So the absolute value of x+3 = 0, i.e. x = -3

The absolute value of 3y-4 = 0, i.e. y = 4/3

So y*(y-x)=52/9

When C is not taken, there are: (1+1) 2=4.

When B is not taken, there are: (4+1) 2=10.

When A is not taken, there are: (10+1) 2=22.

Average value per pear: yuan.

Backwards: When C is taken, there are: (1+1) 2=4.

When B is taken, there are: (4+1) 2=10.

A is taken: (10+1) 2=22.

The average price per pear is yuan.

After A: x 2 -1

After B takes: (x 2 -1) 2 -1

After Cing: [x 4 -1 = 1.]

x-2=20

x=22 yuan.