CosX I 4 is known, SinX tanX 40 is found

cosx=1/4

x in the first. 1. Fourth Quadrant.

by sin x+cos x=1

sinx=±√15/4

If x is in the first quadrant, then sinx = 15 4 and tanx = sinx cosx = 15

If x is in the fourth quadrant, then sinx=- 15 4, tanx=sinx, cosx=- 15

Solution: cosx=1 4, x is an acute angle a of a right triangle, let b=m, c=4m, then a= 15m.

sinx=a/c=√15m/4m=√15/4；

tanx=a/b=√15m/m=√15。

sinx = positive and negative root number (1-cosx squared) = positive and negative root number (1-1 16) = positive and negative root number 15 4

tanx=sinx osx=(plus and minus 15 4) (1 4) = plus or minus 15

sinx = root number (1-cosx squared) = root number 15 4

tanx=sinx cosx=root number 15 4 1 4 = root number 15

Summary. Kiss will be happy to solve the problem for you: if you know tanx=5 12, then: sinx=—5 13 or 5 13cosx=12 13 or —12 13

Knowing tanx=5 12, evaluated.

It is a pleasure to solve the problem for you: if you know tanx=5 12, then: sinx=—5 13 or 5 13cosx=12 13 or pure Qingxian—12 13

Detailed process. Kiss: The answer process is as follows:

According to the title, stare at Wangde: sinx cosx=5 12 and Shi Yun because: sin2x+cos2x=1 so:

sin2x=25 169So:sinx=5 13 or —5 13 is brought in: cosx=12 13 or cosx=—12 13

Kiss: The answer process is like Kai Nuzi Xia: according to the question to stare at Wang De:

sinx cosx=5 12 and Shi Yun because: sin2x+cos2x=1 so: sin2x=25 169 so:

sinx=5 13 or —5 13 in: cosx=12 13 or cosx=—12 13

Kiss: Analysis: This question examines the application and understanding of trigonometric functions, and solves it according to the synchronic known sin2x+cos2x=1.

Extended information: Trigonometric function is one of the basic elementary functions, which is a function in which the angle (the most commonly used radian system in mathematics, the same below) is the independent variable, and the angle corresponds to the coordinates of the intersection point of the terminal edge of any angle and the unit circle or its ratio as the dependent variable. It can also be defined equivalently in terms of the length of the various line segments related to the unit circle.

The trigonometric function of land slag plays an important role in the study of the properties of geometric shapes such as triangles and circles, and is also a basic mathematical tool for the study of periodic phenomena. In mathematical analysis, trigonometric functions are also defined as infinite early series or solutions to specific differential equations, allowing their value to be extended to arbitrary real values, even complex values.

You can think of it that way.

Set the point with search p coordinates as (a, b), c 2 = a 2 + b 2 and have angle x = angle pox so there is cosx = a c

Because cosx=1 4>0

So there are two kinds of tease situations for corner x.

1, the angle x is in the first quadrant, at this time, you might as well let a=1, c=4 then there is b= 15, so there is sinx= 15 4, tanx= 15

2, the angle x is in the fourth quadrant, at this time, you might as well set a=1, c=4 but b is negative, so there is b=- 15, so there is sinx=- 15 4, tanx=- 15

To sum up, there are two answers.

From sinx+cosx= 1 5, we get sinx= 1 5 -cosx

Substituting Zhisou sin 2 x + cos 2 x = 1 obtains: (5 cosx-4) (5 cosx + 3) = 0

When cosx= 4 5 or cosx=- 3 5, sinx=- 3 5 and 0 x and sinx 0 are obtained.

When cosx=- 3 5, sinx= 4 5 , tanx=- 4 3

There is 1 miswriting. It should be written as coxx.

I have a process, on the diagram. There are pictures and truths. You use the computer to log in and then look at the picture.,Mobile phone login with a laughing eggplant record may not be able to see it.。 You log in with your computer to watch. You can't see it with your phone! Numerator and denominator multiplication (cosx

sinx), and then molecularized to 1

sin2x, the denominator becomes (cosx) 2-(sinx) 2, and then 2(cosx) 2-1. Then sin2x=2tanx (1

tanx)^2)

cosx)^2=1/(1

tanx) 2) = 1 5, and the result is -3. where is the square.

x(V4,3V4).

i.e. sinx >cosx

sinx+cosx=5/13√2

Then the square gets the answer of burying the sail.

sinx) 2+2sinxcosx+(cosx) 2=50 169. sinx-cosx)^2

sinx) 2+(cosx) 2-2sinxcosxso. sinx -cosx=12 13 2 and sinx+cosx=5 13 2 are obtained.

sinx = 17 26 2, cosx = -7 26 2 and the car burns. 1-tanx)/(1+tanx)

1+17 Bend Hui 7) 1-17 7).

Facts are facts.

Solution: It is known that sinx+cosx=-7 5 (1) Because sinx -1, cosx -1, so:

For the above equation to be true, it is necessary to make :sinx<0 and cosx<0 then tanx=sinx cosx>0

1) The two sides of the formula are squared:

sin x+2sinx*cosx+cos x=49 25, i.e. 1+2sinx*cosx=49 25

The solution yields sinx*cosx=12 25

and sin x+cos pin x 1, so:

sin²x+cos²x)/(sinx*cosx)=1/(12/25)=25/12

That is, sinx cosx +cosx sinx=25 12, so tanx+1, the former tanx=25 12, then 12tan x-25tanx+12=0

3tanx-4)(4tanx-3)=0

The solution yields tanx=4 3 or tanx=3 4

So 1 tanx = 3 4 or 4 3