Read the following material, material: trial equation AX = B solution: when ab ≠ 0, the equation has a unique solution x = B of a; when a = b = 0 When a = 0, B ≠ 0, the equation has no solution (1) It is known that the equation a (2x-1) + 3x-2 about X has no solution; (2) Solving the equation (3-x) M = n (x-3) (m ≠ - n) about X

Read the following material, material: trial equation AX = B solution: when ab ≠ 0, the equation has a unique solution x = B of a; when a = b = 0 When a = 0, B ≠ 0, the equation has no solution (1) It is known that the equation a (2x-1) + 3x-2 about X has no solution; (2) Solving the equation (3-x) M = n (x-3) (m ≠ - n) about X

A (2x-1) + 3x-2? Which equation is this? It's wrong

Given a + B + C = 2 A2 + B2 + C2 = 3 A3 + B3 + C3 = 4, find A4 + B4 + C4 =?

The fruit shop brought in a batch of fruits and sold 50% of them on the first day. Pears accounted for 1 / 4 of the total number of pears, including 120 kg of apples. The ratio of the remaining pears to apples was 3:2
The fruit shop brought in a batch of fruits and sold 50% of them on the first day. Pears accounted for 1 / 4 of the total number of pears, of which apples were 120 kg. The ratio of the remaining pears to apples was 3:2. This batch of fruits used to be several thousand grams?
Equation, arithmetic all need

Pear x, apple y
(x+y)/2-1/4*x=120
3/4*x*2=(y-120)*3

The three apprentices cooperate to process a batch of parts in five days. Apprentice a completes 12 of apprentice B's and apprentice B completes 12 of master's. If apprentice a works alone for two days, how many days will apprentice B cooperate with master to complete the rest of the work?

The efficiency of apprentice a: the efficiency of apprentice B: the efficiency of master is 1:2:4. The total number of shares: 1 + 2 + 4 = 7. The efficiency of apprentice a: 15 × 17 = 135; the efficiency of apprentice B and master: 15 × 2 + 47 = 15 × 67 = 635; 1-135 × 2 = 1-235 = 33353335 △ 635 = 5.5 (days) a: it will take 5.5 days to complete ．

What is the phase relationship between current and voltage in pure capacitor AC circuit? A, lead 90 B, lag 90 C, in phase

A

During the National Day holiday, Xiaoming's family drove out to travel. When they got to the entrance of a highway, Xiaoming noticed that the highway was 180 km long
The speed requirements are as follows: the minimum speed limit is 60 km / h, and the maximum speed limit is 120 km / h. Xiao Ming looks at his watch. It's 10:00 in the morning. He quickly calculates and tells his father what period of time he must arrive at the exit of the expressway before he will break the rules. Please explain by calculation what period of time Xiao Ming told his father

If it's a math problem, then it's like this: the longest time: 180 / 60 = 3 hours; the shortest time: 180 / 120 = 1.5 hours; then it should be in 10 + 1.5 = 11.5-10 + 3 = 13. That is to say, it won't violate the rules until you arrive at the high-speed exit between 11:30 and 13:00

Why can the m-th power of nonzero n-order square matrix a be a zero matrix. M ≥ 2

Just a ^ n = O (n)

What are "triangle rule" and "vector triangle"?

Triangle rule refers to the combination of two forces (or any other vector). The resultant force should move the starting point of one force to the ending point of another force, and the resultant force should be from the starting point of the second force to the end point of the first force
Vector representation is a physical quantity represented by a line segment and an arrow. The length of the line segment represents the quantity of the vector, and the arrow represents its direction
If there are two forces in different directions, use a proper amount of triangles to find out the size of their resultant force, connect the tail of the second force to the head of the first force, and their resultant force is a vector that the tail of the first force points to the head of the second force. After drawing, you can see that the three constitute a triangle, which is the so-called vector triangle

A teacher of a school takes students to Beijing to attend a summer camp. Travel agency a says, "if the teacher buys a full ticket, the rest of the students can enjoy half price discount." travel agency B says, "including the teacher, all the students will get a 60% discount on the full ticket." if the ticket price to Beijing is 240 yuan. (1) when the student is a student, he will get a 60% discount on the full ticket______ The two travel agencies charge the same per person hour? (2) When the number of students is less than or more than how many, which travel agency is more favorable?

Suppose there are X students. (1) ∵ the two travel agencies charge the same fees, so 240 + 240 × 0.5x = (x + 1) × 240 × 0.6 to get x = 4; (2) when a travel agency is more preferential: 240 + 120x ＜ 144 (x + 1) to get x ＞ 4 when B travel agency is more preferential: X ＜ 4 answer: when the number of students is 4, the two travel agencies charge the same fees. When the number of students is more than 4, a travel agency is more preferential, when the number of students is less than 4 B travel agency is more favorable

How to prove LIM (a ^ X - 1) / x = LNA
x-0

L'hostpital rule:
lim{x->0} (a^x -1)/x = lim{x->0} a^x*lna/1 = lna