One end of the line is a vertical plane, and the other end of the line forms an included angle, which is the plane angle of the line. Sine value is the value that the length of the opposite side in a right triangle is greater than the length of the hypotenuse. The sine value of any acute angle is equal to the cosine value of other angles, and the cosine value of any acute angle is equal to the sine value of other angles. Sine, cosine and tangent formulas of half angle; Power reduction formula of trigonometric function.
The included angle between a line and a plane refers to the acute angle or right angle formed by the vertical line passing through a point on a straight line that is not parallel to the plane and the connecting line between the intersection of this straight line and the plane and the intersection of the original straight line and the plane. The angle formed by the oblique line and its projection on the plane is the angle between the straight line and the plane.
Sine value:
Sine value is the value that the length of the opposite side in a right triangle is greater than the length of the hypotenuse. The sine value of any acute angle is equal to the cosine value of other angles, and the cosine value of any acute angle is equal to the sine value of other angles.
Chord value is the value that the length of the opposite side in a right triangle is greater than the length of the hypotenuse. The sine value of any acute angle is equal to the cosine value of other angles, and the cosine value of any acute angle is equal to the sine value of other angles. sin 30 = 1╱2sin45 =√2╱2sin60 =√3╱2sin90 = 1 sin 180 = 0 sin 0 = 0 sin 270 =- 1 .
Sin2A=2sinA cosA .
cos2a=cos^2a-sin^2a= 1-2sin^2a=2cos^2a- 1。
tan2A=(2tanA)/( 1-tan^2A)。
Basic relations of trigonometric functions with the same angle;
Reciprocal relation: quotient relation: square relation:
tanα cotα= 1 .
sinα cscα= 1 .
cosαsecα= 1 sinα/cosα= tanα= secα/CSCα.
cosα/sinα= cotα= CSCα/secαsin 2α+cos 2α= 1 .
1+tan2α=sec2α.
1+cot2α=csc2α.