Let f (x) be defined as R, and for X, y ∈ R, f (XY) = f (x) + F (y). If f (8) = 3, then f (2) = 1___ ．

Let f (x) be defined as R, and for X, y ∈ R, f (XY) = f (x) + F (y). If f (8) = 3, then f (2) = 1___ ．

∵ f (8) = f (4) + F (2) = 3f (2) = 3 ∵ f (2) = 1 ∵ f (2) = 2F (2) = 1 ∵ f (2) = 12, so the answer is: 12

Given the function f (x), if x.y belongs to R, f (XY) = f (x) + F (y), and f (x) is a decreasing function in the domain of definition
Find f (1)
If f (2a-3) < 0, try to determine the value range of A

Let x = y = 1, substitute f (XY) = f (x) + F (y), where f (1) = f (1) + F (1), f (1) = 0;
F (2A - 3) < 0 = f (1), that is, f (2A - 3) < f (1). Since f (x) is a decreasing function in the domain of definition, 2A - 3 > 1 leads to a > 2

It is known that the function f (x) defined on R + satisfies the following conditions: (1) f (XY) = f (x) + F (y) for any x, y in the domain of definition; (2) f (x) < 0 when x > 1; (3) f (2) = - 1 (1) find the value of F (8); (2) prove that the function f (x) is a decreasing function on (0, + ∞); (3) solve the inequality: F (2x + 2) - f (2X-4) < - 3

(1) In F (XY) = f (x) + F (y), let x = y = 2, f (4) = f (2) + F (2) = - 2, let x = 2, y = 4, f (8) = f (2) + F (4) = - 3, then f (8) = - 3; (2) let 0 ＜ x1 ＜ x2 ＜ + ∞, then x2x1 ＞ 1, then f (x2x1) ＜ 0, f (x2) - f (x1) = f (x2x1 ·

As shown in the figure, it is known that s is a point out of the plane of the parallelogram ABCD, m and N are points on SA and BD respectively, and SMMA = bnnd. Then the line Mn______ Plane SBC

It is proved that bnnd = bgag can be obtained by making ng ∥ ad through N, intersecting AB with G and connecting mg. According to the known condition bnnd = SMMA, SMMA = bgag, ∥ mg ∥ sb. ∩ mg ⊄ plane SBC, sb ⊂ plane SBC, ⊂ mg ∥ plane SBC. Ad ∥ BC, ∥ ng ∥ BC, ng ⊄ plane SBC, BC ⊂ plane SBC ∩ plane SBC ∩ plane MNG, ⊂ plane MNG, ∥ plane SBC The answer is ‖

What is the area of a sector with a radius of 4cm if its perimeter is equal to that of the semicircle where the arc is located
If its circumference is equal to the circumference of the semicircle in which the arc is located
What does this sentence mean

If A2, A3 and A6 in the arithmetic sequence (an) with non-zero tolerance are proportional, then the common ratio q is_____ Requirements (detailed process)

Then A3 & sup2; = a2a6
(a1+2d)²=(a1+d)(a1+5d)
a1²+4a1d+4d²=a1²+6a1d+5d²
2a1d+d²=0
d≠0
d=-2a1
So q = A3 / A2
=(a1+2d)/(a1+3d)
=-3a1/(-5a1)
=3/5

About 80 words about Chinese Spring Festival

The Spring Festival
Everyone,young and old,rich and poor,looks forward to celebrating the noisiest,most joyous and longest festival of the year.Chinese New Year is not celebrated at a hotel or supper club with revelers donning silly paper hats,drinking liquor and champagne,eating sumptuously,blowing whistles,twirling noisy rattles and throwing confetti while singing "Auld Lang syne" and dancing until the wee hours of the morning.In China,New Year's Day is a solemn occasion.Every family performs religious rites at the family altar.This is the time for a family reunion.All family quarrels have been amiably settled and forgotten.
Before the eve of the New Year,everyone tries to come back home from every corner of the country to join the entire family,just like Americans' practice for Christmas,to greet the New Year.A New Year big dinner is served.After the meal,the table is cleared, dishes washed and put away.Then it is time to undertake final preparations to meet the New Year.

In quadratic function, if two points of right triangle are known on function graph, how to find the third point
All three points are on the function image

There is no universal solution

The length of a cuboid is 8 cm and its width is half of its length. The surface area of the cuboid is () and its volume is ()

The cuboid is 8 cm in length, half in width and 2 cm in height. Its surface area is 112 square cm and its volume is 64 cubic cm

Sin (PAI / 3-x) equals SiN x?

Not equal to
sin(2kπ+x)=sinx
sin(π-x)=sinx