If 3x: 3 = 4:1, then x is equal to?: if 2a and 1-A are opposite numbers, then a is equal to?

If 3x: 3 = 4:1, then x is equal to?: if 2a and 1-A are opposite numbers, then a is equal to?

3x*1=3*4,x=4
2a=-(1-a),a=-1

When x=___ 3x-7 and - 2x + 9 are opposite to each other

3x-7 and - 2x + 9 are opposite numbers
3x-7-2x+9=0
x=-2

When x equals (), 2x + 9 and 3-x are opposite numbers. When x equals (), 2x + 9 and 3-x are opposite numbers

If 2x + 9 and 3-x are opposite to each other, the sum is equal to 0
So (2x + 9) + (3-x) = 0
2x+9+3-x=0
x+12=0
x=-12

Finding the derivative of y = xtanx

tanX+X/cosX2

Calculating the derivative of a function
Calculate the derivatives of the following functions
1.y=sin(2x/ (1+x^2))
2. Y = in (x + change sign (1 + x ^ 2))

The derivative rule of composite function: 1. Y = sin (2x / (1 + x ^ 2)) y '= cos [2x / (1 + x ^ 2)] * [2 (1 + x ^ 2) - 4x ^ 2] / (1 + x ^ 2) ^ 2 = 2cos [2x / (1 + x ^ 2)] * (1-x ^ 2) / (1 + x ^ 2) ^ 2.2. Y = in [x + √ (1 + x ^ 2)], y' = 1 / [x + √ (1 + x ^ 2)] * [1 + X / √ (1 + x ^ 2)] = 1 / √ (1 + x ^ 2)

The whole process of derivation of y = TaNx ^ 3

y = tan x³
y' = 3x²(sec²x³)
y = (tanx)³
y' = 3(tax²x)sec²x

Finding the derivative of y = sin (4x / 39), y

y‘=(4/39)*cos(4x/39)
First, we obtain cos by deriving sin
Then the derivative of 4x / 39 gives 4 / 39
And then multiply to get the answer, this is the chain derivation rule, the method of compound function derivation

Why does cos appear in the derivative of sin ^ 3 (4x)?
Such as the title

Y = Sin & sup3; (4x) is a three-layer composite relation: y = u & sup3;, u = sin, V, v = 4x. We usually say that the derivation of X is the derivation of X. the derivation of this composite function needs to use chain rule

The function y = sin (2x + π / 6) has a center of symmetry

The center of symmetry of sin is the point of intersection with the x-axis
y=sin(2x+π/6)=0
2x+π/6=kπ
x=kπ/2-π/12
So it's (K π / 2 - π / 12,0)

The monotone decreasing interval of the function y = sin (x + π 4) is___ ．

Let 2K π + π 2 ≤ x + π 4 ≤ 2K π + 3 π 2, K ∈ Z, obtain 2K π + π 4 ≤ x ≤ 5 π 4 + 2K π, so the monotone decreasing interval of function y = sin (x + π 4) is [2K π + π 4, 5 π 4 + 2K π], K ∈ Z, so the answer is: [2K π + π 4, 5 π 4 + 2K π], K ∈ Z