sin sin, 1 if , are the first quadrant angles, try to determine the relationship between cos and co

1) Because the sum of the squares of cos and sin is 1, the angle is the same, and because it is the first quadrant, sin cos sin cos is positive, and because sin > sin, cos > cos.

2) Because it is the second quadrant angle, both tan and tan are negative, but sin and sin are positive, and sin > sin, from 1) we can know |cosβ|>cosα|, but it's all negative, so |tanα|=|sinα/cosα|>tanβ=sinβ/cosβ|, go to the absolute value, because it is negative, so tan

sin > sin ,1) if , are the first quadrant angles, let = 1+2k, = 1+2k, and 1 and 1 are both acute angles, k z.

Then sin = sin 1, sin = sin 1, from sin > sin, get sin 1>sin 1, 1> 1, then cos 1sin , get sin 1>sin 1, 1< 1, then tan 1Note: In the acute angle region, the sine function is an increasing function, and the cosine function is a decreasing function;

In the obtuse region, the sinusoidal function is a decreasing function and the tangent function is an increasing function.

sin 0, at 3,4 like the virtual limit.

tan 0 in 2,4 elephant yards rubber limit difference mold.

If sin 0 and tan 0, then is the 4th quadrant angle.

The point p(sin2,cos) is located in the second quadrant, sin2 = 2sin cos 0, cos 0, that is, the hall source does not have sin 0, and cos 0, so the angle is the fourth fissure quadrant angle, which is disguised.

So the answer is: four

The angle is the first quadrant angle, and the angle - is the fourth quadrant angle, and it will be rotated counterclockwise to get - it must be in the second quadrant

- The terminal edge is in the second quadrant.

- is the angle of the second quadrant.

So the answer is: two

sin >0, is the second quadrant angle of the first round, and tan <0, is the second or fourth quadrant angle, and the intersection is obtained: is the second quadrant angle

Solution: Let's only discuss the case of (0, 2), and the other plus periods are the same.

Let y=sin +cos = 2sin(a+4)a-range(0, 2).

A+4 range (4,3,4).

So the value of y is (1, 2).

So y>1

i.e. sin + cos >1

Because is the second quadrant angle.

Remember a password.

One is full of honor, two are sine, three are cut, and four are cosine.

A complete one. It means that in the first quadrant of Qing Pong Tsai, sin, cos, tan, and cot are all positive and coincidental.

Two sine. It means that in the second quadrant sin is positive.

Three-by-two cuts. It means that in the third quadrant, tan, cot is positive.

Four cosine. This means that the cos is positive in the fourth quadrant.

So. sinθ>0

cosθ

tanθ=(sinθ)/cosθ)

sinθ)/tanθ)=cosθ.

The inequality in the problem is equivalent to cos 0

Combined with the relationship between the trigonometric function value and the angle, it can be seen.

The original proposition of the four-quadrant angle of the first carrier or the fourth quadrant angle of the argument is <==cos 0.