If an odd function f (x) has f (x) = f (2-x) for any X in the domain of definition, then f (x) is a periodic function. Why= Because it is an odd function f (x) = - f (x); f (- x) = f (2 + x) = f (x), can we prove that f (x) is a periodic function by F (2 + x) = f (x)?

If an odd function f (x) has f (x) = f (2-x) for any X in the domain of definition, then f (x) is a periodic function. Why= Because it is an odd function f (x) = - f (x); f (- x) = f (2 + x) = f (x), can we prove that f (x) is a periodic function by F (2 + x) = f (x)?

The definition of periodic function is f (x) = f (x + T). So, as long as you can use the known conditions to get the formula F (x) = f (x + T), you can explain that f (x) is a periodic function. The odd function f (x) has f (x) = - f (x). Then when f (x) = f (2-x), replace x with - x, you can get f (- x) = f (2 + x) = f (x), that is, f (x) = f (x + 2)

How to solve the equation of 10x-5x (20-x) = 170?

10X-5x(20-X)=170
10X-100+5X=170
15X-100=170
15X-100+100=170+100
15X=270
X=18

Given that the two coordinate axes are the symmetry axes of the ellipse, the distance between the two guide lines is 36, and the distance between a point on the ellipse and the two focal points is 9 and 15
Known that the two axes are the axis of symmetry of the ellipse, the distance between the two directrix is 36, and the distance between a point on the ellipse and the two focal points is 9 and 15. Solve the elliptic equation. Big brother, help

The right directrix equation is: x = 18,
a^2/c=18,
2a=9+15=24,
a=12,
144/c=18,c=8,
b^2=a^2-c^2-144-64=80,
The elliptic equation focusing on X axis is: x ^ 2 / 144 + y ^ 2 / 80 = 1,
The elliptic equation with focus on Y axis is y ^ 2 / 144 + x ^ 2 / 80 = 1,

How much is 3 / 2 times X-1 = 3 / 3 x
2 / 3x-1 = 3 / X

Double six on both sides
9(x-1)=2x
9x-9=2x
9x-2x=9
7x=9
x=9÷7
X = 9 / 7

Square of (sin35 degree + cos35 degree) - 2sin35 Degree * cos35 degree=
Detailed process to Oh!
This is my first time. I don't have many points. Please help me. I'll make up the points for you later

The square of (sin35 ° + cos35 °) - 2sin35 ° * cos35 °
=Square of sin35 ° + 2sin35 ° * cos35 ° + square of cos35 ° - 2sin35 ° * cos35 °
=Sin35 ° square + cos35 ° square
=Sin35 ° square + sin55 ° square (∵ sin ∠ a = cos ∠ B (∠ B = 90 ° - a), cos ∠ a = sin ∠ b)
=1 (∵ sin ∠ A's square + sin ∠ B's Square = 1)

How to solve (x + 50) × 3 / 5 = 9 / 10x equation

Multiply 3 / 5 into brackets, 3 / 5 * x + 30 = 9 / 10 * x, then move the term, move the one with X to one side, and finally get x = 100

How much is 5 / 7 times 60
It takes Master Li 45 minutes and Master Wang 7 / 5 hours to process a part. Who can do it faster?
Explain

45 minutes = 3 / 4 hours > 3 / 4 > 5 / 7, so Master Wang can do it faster

How to solve the equation of 3x = 5 (x-4)

3x＝5（X－4)
3x＝5x－20
3x－5x＝﹣20
﹣2x＝﹣20
x＝10

sin20^2+cos50^2+sin30*cos70=?

Original formula = sin ^ 2 20 ° + cos ^ 2 50 ° + sin (50 ° - 20 °) - sin (50 ° + 20 °)
Using the formula of sum of two angles
=sin^2 20°+cos^2 50°+（sin50°cos20°-sin20°cos50°）（sin50°cos20°+sin20°cos50°）
=sin^2 50°cos^2 20°-sin^2 20°cos^2 50°+sin^2 20°+cos^2 50°
Using the formula of reducing power
=[（1-cos100°）/2 *（1+cos40°）/2]-[（1-cos40°）/2 *（1+cos100°）/2]+(1-cos40°)/2 +(1-cos100°）/2
Put forward 1 / 4 and sort it out
=1/4 *[(1-cos100°+cos40°-cos100°cos40°)-(1+cos100°-cos40°-cos100°cos40°)+2+2cos100°+2-2cos40°]
=1/4*4=1
2 sinA sinB = cos(A-B) - cos(A+B)
sin30°sin70°=cos(30°-70°)-cos(30°+70°)=cos40°-cos100°
Sin20 ° square = (1-cos2 * 20 °) / 2 = (1-cos40 °) / 2
Similarly, the square of cos50 ° is = (1-cos2 * 50 °) / 2 = (1-cos100 °) / 2
The original formula = (1-cos40 °) / 2 + (1-cos100 °) / 2 + (cos40 ° - cos100 °) / 2 = 1

8x + 4x = 56, a series of equations, but also to solve

(8+4)x=56
x=56÷12
x=14/3