If we know that a and B are nonzero, asin α + bcos α ACOS α - bsin α = Tan β, and β - α = π 6, then Ba is equal to () A. 3B. 33C. -3D. -33

If we know that a and B are nonzero, asin α + bcos α ACOS α - bsin α = Tan β, and β - α = π 6, then Ba is equal to () A. 3B. 33C. -3D. -33

From the tangent of β = α + π 6, Tan β = Tan (α + π 6) = Tan α + Tan π 61 Tan α Tan π 6 = Tan α + 331-33tan α = asin α + bcos α ACOS α - bsin α = Tan α + BA1 Batan α. So Ba = 33, so the answer is B

Trigonometric function of sum and difference of two angles (19 20:39:29)
Given Tan (a-45) = - 2, find the value of A

tan(a-45°）=(tana-tan45°）/(1+tana*tan45°）=(tana-1)/(1+tana)=-2
tana=-1/3 a=-arctan(1/3)

Lim sin3x -------- = how much? X-0 x + tan7x
Lim sin3x
----------------
x-0 x+tan7x

Lim 3x
----------------
x-0 x+tan7x
Lim 3
= ----------------
x-0 1+tan7x/x
=3/8

Find the extremum of function f (x, y) = x & # 179; - 4x & # 178; + 2xy-y & # 178; + 5

Let f'x = 3x & # 178; - 8x + 2Y = 0 (f'x denotes the partial derivative of F (x, y) with respect to x, and others are the same) f'y = 2x-2y = 0  X1 = 0, Y1 = 0. Or x2 = 2, y2 = 2  a = f '', XX = 6x-8, B = f '', xy = 2, C = f '', YY = - 2  B &  178; - AC = 2 &  178; - (- 2) (6x-8) = 12 (x-1)  when X1 = 0, Y1 = 0, a = - 8

Elevation calculation
The absolute elevation is 22.8, the benchmark standard is 0.42, and the measured points are 1.38, 2.01, 2.71, 2.91 and 3.08 respectively. What are the corresponding elevations of these points and how to calculate them?

The topic is that the reading of the level gauge of the datum point is 0.42, and the reading of the measuring ruler of the measured points are 1.38, 2.01, 2.71, 2.91 and 3.08 respectively. If you understand correctly, the absolute standard heights of the measured points are as follows:
22.8+（0.42-1.38）=21.84
22.8+（0.42-2.01）=21.21
22.8+（0.42-2.71）=20.51
22.8+（0.42-2.91）=20.31
22.8+（0.42-3.08）=20.14

It is proved that y = xsin1 / X is infinite when x → 0
Explain what principle to use definition to prove that I am under great pressure to learn advanced mathematics

Infinitesimal when y = xsin (1 / x) is x → 0
lim(x→0) y
=lim x*sin(1/x)
Because sin (1 / x) is a bounded quantity;
X tends to zero and is infinitesimal
The product of bounded quantity and infinitesimal quantity is infinitesimal quantity
Therefore,
=lim x*sin(1/x)
=0
If you don't understand, please ask

60% - 40% x = 45

0.6-0.4x=45
0.4x=0.6-45
x=-44.4÷0.4
x=-111

How much is 3 / 1 + 6 / 1 + 10 / 1 + 15 / 1 + 21 / 1 + 28 / 1 + 36 / 1 + 45 / 1?

…… 3+6+10+15+21+28+36+45 =164
1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45
=77/105

1 / 2x-1 / 3Y = 1 - 1 / 3x-y = 2 / 3, solve the equation··········

Multiply both sides of the first equation by 3 to get
3 / 2x-y = 3 take this formula minus the second one
11/6x=7/3
x=14/11
y=-12/11

A equals B times 2, so what is a minus B, and what is a divided by B

b,2