In a cuboid water tank of 15 decimeters long and 12 decimeters wide, there is 10 decimeters deep water. If a square iron block with 2 decimeters long edge is sunk in the water, then How high is the water in the tank now?

After sinking into the cube, the water in the tank rises by X decimeters
15 * 12 * x = 2 ^ 3, the solution is x = 2 / 45,
As a result, the water in the tank is now 10 + 2 / 45 decimeters high

In a square water tank full of water with 20 sides (measured from the inside), there is a rectangular iron block 16 cm long and 10 cm wide
After the block is taken out, the water in the water tank drops by 2 cm. What is the height of this iron block? I want to calculate and explain

16*16*2/(16*10)=3.2cm
The volume of the water drop is just the volume of the rectangular iron block. If you don't understand it, you can add it!

Is the derivative of ∫ (x ~ x) f (x) DX f (x)? The same upper and lower limits
two thousand one hundred and thirty-four

∫ (x ~ x) f (x) DX = 0 because the upper and lower limits are the same
So the derivative is also zero

Principle of protein determination

The principle of different test methods is different. The principle of Kjeldahl method is introduced as follows: Kjeldahl method is used to measure protein content: according to Kjeldahl method, the nitrogen content and nitrogen content in protein are 1 / 6.25 (16%), so the protein content can be calculated

Finding differential e ^ X / y-xy = 0
My own answer: dy = - x ^ 2Y + Y / XY ^ 2 + X, the differential of composite function + implicit function will tell me, right

Move the term, take the logarithm, X / y = LNX + LNY, multiply it
Take the differential and get DX = (LNX) dy + Y / xdx + (LNY + 1) dy
Dy / DX = 1 / (LNX + Y / x + LNY + 1)
Do you want to do this?

Y = Xe ^ (- x), find the Nth derivative of Y

Y = Xe ^ (- x), so ye ^ x = X
The recurrence formula y (n) e ^ x + y (n-1) e ^ x = (- 1) ^ n can be obtained by continuous n-times derivation
So y (n) = (- 1) ^ n (x-n) e ^ (- x)

The numerator and denominator of 13 numerator 1 can be divided into 3 numerator 1?

The calculation process is that the numerator denominator of 1 / 13 plus the unknown x is equal to 1 / 3. Solving the equation, X is 5

y′+2xy=4x．

Because y '+ 2XY = 4x is a first order linear differential equation, we use the constant variation method to solve the problem, P (x) = 2x, q (x) = 4x, so y = e - ∫ P (x) DX (∫ e ∫ P (x) dxq (x) DX + C) = e - ∫ 2xdx (∫ e ∫ 2xdx · 4xdx + C) = E & nbsp; − X2 (∫ ex2 · 4xdx + C) = E & nbsp; − X2 (2 ∫ ex2dx2 + C) = 2 + E & nbsp; − x2c

(1) If M & # 178; + 2Mn + 2n & # 178; - 6N + 9 = 0, find the value of M / N & # 178
(2) Given: 4m + n = 90, 2m-3n = 10, find the value of (M + 2n) &# 178; - (3m-n) &# 178

(1) This paper will be 178; + 2Mn + 2n + 2n (n + 2n + 2n + 2n; (n + 2n + 2n + 2n; (2n + 2n + 9 = 0 (M + n) \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\n-3m + n) = (4m + n

In a multiplication formula, the multiplier is 5 / 3, and the product is 48 more than the multiplicand. What is the product?

Multiplicand: 48 (5 / 3-1) = 72
Product: 72 × 5 / 3 = 120

In a cuboid water tank of 15 decimeters long and 12 decimeters wide, there is 10 decimeters deep water. If a square iron block with 2 decimeters long edge is sunk in the water, then How high is the water in the tank now?