Tan α = - √ 2, and α is in the fourth quadrant. Find sin α, cos α, cot α Answer online

Tan α = - √ 2, and α is in the fourth quadrant. Find sin α, cos α, cot α Answer online

COTA = 1 / Tana 1 + (Tana) square = 1 / (cosx) square cosx = (root 3) / 3 the fourth quadrant COS is positive SiNx = - (Radix 6) / 3
The fourth quadrant sin is negative

If cot (COS β) * Tan (sin β) > 0, try to determine the quadrant of β And explain the reasons

If cot > 0 and Tan > 0, cos belongs to (0,0.5 school) sin belongs to (0,0.5 school)
One quadrant
If cot

It is known that sin α / √ (1 + cot ^ 2) - cos α / √ (1 + Tan ^ 2) = - 1 is the angle to judge which quadrant α is

One quadrant: left = sin ^ 2a-cos ^ 2A = - cos2a = - cos2a = - 1, a = 0, not in the definition domain second quadrant: left quadrant: left = sin ^ 2a-cos ^ 2A = - cos2a = - 1, a = 0, not in the definition domain second quadrant: left = left = sin ^ 2A + cos ^ 2A = 1 ≠ - 1, three quadrants: left = - Sin ^ 2A + cos ^ 2A = 1 ≠ - 1 three quadrants: left = - Sin ^ 2A + cos ^ 2A = cos2a = cos2a = - 1, a = π / 2, is not in the fixed...It's a good idea

It is known that cos α = - 4 5, and α is the third quadrant angle. Find the values of sin α and Tan α

∵cosα=-4
And α is the third quadrant angle,
∴sinα=-
1−cos2α=-3
5，
Then Tan α = sin α
cosα=3
4．

It is known that α is the fourth quadrant angle, and f (α) = sin (α - π / 2) cos (3 / 2 π + α) Tan (π - α) / Tan (- α - π) sin (- π - α) (1) Simplify f (α); (2) If cos (α - π / 2) = - 1 / 4, find f (α)

f(α)=sin(α-π/2)cos(3/2π+α)tan(π-α)/tan(-α-π)sin(-π-α)
= - cos(α)sin(α)( - tan(α)) / ( - tan(α))sin(α)
= - cos(α)
Cos (α) is positive because α is the fourth quadrant angle
F (α) = - cos (α) = - radical (1-sin ^ 2 (α)) = - radical (1-cos ^ 2 (α - π / 2)) = - radical (1-1 / 16)
=- root 15 / 4 (minus quarter root 15)

What is the formula of double angle? What is the positive and negative situation of sin, cos and tan in the quadrant?

Double angle formula:
cos2x=(cosx)^2-(sinx)^2=2(
cosx)^2-1=1-2(sinx)^2
tan2x=2tanx/[1-(tanx)^2]
Sine function is positive in the first and second quadrants and negative in the third and fourth quadrants
Cosine function is positive in the first four quadrants and negative in the second and third quadrants
The tangent function is positive in the first three quadrants and negative in the second and fourth quadrants

Double angle formula of sin, cos and Tan

sin2α=2sinαcosα
cos2x=2cosx^2-1=1-2*sinx^2=cosx^2-sinx^2
tg2x=2tgx/(1-tgx^2)

If sin (π + a) = 4 / 5, and a is the fourth quadrant angle, then the value of COS (A-2 π) is

sin(π+a)=-sina=4/5, sina=-4/5
cos（a-2π）=cosa
A is the fourth quadrant angle, cosa > 0
cosa=√(1-sin^2a)=3/5

Sin @ = 3 / 5 cos @ = - 4 / 5 angle @ in which quadrant

third

Cos (α - 75 °) = - 1 If α is the fourth quadrant angle, sin (105 ° + α) = 3___ .

∵cos（α-75°）=-1
And α is the fourth quadrant angle,
∴sin（α-75°）=-
1-(-1
3)2=-2
Two
3，
Then sin (105 ° + α) = sin [180 ° + (α - 75 °)] = sin (α - 75 °) = 2
Two
3．
So the answer is: 2
Two
Three