The solution equation: x2-2 [x] - 3 = 0

The solution equation: x2-2 [x] - 3 = 0

∵ x ^ - 2! X! - 3 = 0 ∵! X! ^ - 2! X! - 3 = 0 ∵ (! X! - 3) * (! X! + 1) = 0 ∵ X! + 1 ≠ 0 ∵ X! - 3 = 0 ∵ the solution of the original equation is x = 3. Or x = - 3

Solution equation: (x-3) 2 + 4x (x-3) = 0 answer: X1 = 3, X2 = 3, why are there two results?

Solution 1: (x-3) 2 + 4x (x-3) = 0 (x-3) (x-3 + 4x) = 0, x-3 = 0, 5x-3 = 0, x = 3, x = 3 / 5 solution 2: X & sup2; - 6x + 9 + 4x & sup2; - 12x = 05x & sup2; - 18x + 9 = 0, use the formula x = {- B ± √ (b ^ 2-4ac)} / 2a, B & sup2; get: X1 = 3, X2 = 3, X2 = 5

(x + 3.2) x2 = 10.8

x+3.2=10.8／2
x=5.4-3.2
x=2.2

A round board with diameter of a + B, and two circles with diameter of a and B are dug out, then the area of the remaining board is

=[0.5(a+b)]^2*π-(0.5a)^2*π-（0.5b）^2π
[(=a+b)^2-a^2-b^2]*1/4*π
=0.5abπ

As shown in the figure, a circular steel plate with diameter of a + B is excavated from which two small circles with diameter of a and B are respectively excavated. Then the area of the remaining steel plate (shaded part) is ()
A. πab2B. πab4C. 2πabD. πab

According to the meaning of the title: s shadow = (a + B2) 2 π - (A2) 2 π - (B2) 2 π = ab π 2

There is a round board with a diameter of 2A + B. dig out the two circles with a diameter of 2a and B respectively. What is the area of the remaining board?

There is a round board with a diameter of 2A + B. dig out the two circles with a diameter of 2a and B respectively. What is the area of the remaining board?

Large circle area = π (2a + B2) 2, small circle area = π (2A2) 2 + π (B2) 2, so the remaining area = π (2a + B2) 2 - [π (2A2) 2 + π (B2) 2] = ab π

There is a round board with a diameter of 2A + B. dig out the two circles with a diameter of 2a and B respectively. What is the area of the remaining board?

Large circle area = π (2a + B2) 2, small circle area = π (2A2) 2 + π (B2) 2, so the remaining area = π (2a + B2) 2 - [π (2A2) 2 + π (B2) 2] = ab π

There is a drawer 50 cm long, 40 cm wide and 12 cm high. How many square decimeters of wood do you need to make this drawer?

There is a drawer which is 50cm long, 40cm wide and 21cm high. How many square decimeter boards do you need to make this drawer?

50 * 40 + (40 * 21 + 50 * 21) * 2 = 5780 (square centimeter) = 57.8 (square decimeter)