Question

关于sin, cos, tan

Answer 1

更新1:

麻烦可唔可以比埋d step我?!

1) a. cos(180 + x) + cos(180 - x) a. = (-cosx) + (-cosx) a. = -2cosx b. cos(126)cos(36) + sin(126)sin(36) b. = cos(126 - 36) b. = cos90 b. = 0 ===== 2) a. There are 2 possible solutions. a. (sine is -ve in the 3rd/4th quadrants.) b. The solutions are found in the 3rd and 4th quadrants. c. sinθ = +0.4321 c. Refernce angle θ = 25.6 d. The solutions are found in the 3rd and 4th quadrants. d. ( ) = 180 + 25.6 ororor ( ) = 360 - 25.6 d. ( ) = 205.6 ororor ( ) = 334.4 ===== 3) a. 6cos( ) + cos( ) - 1 = 0 a. [2cos( ) + 1] [3cos( ) - 1] = 0 a. 2cos( ) + 1 = 0 ororor 3cos( ) - 1 = 0 a. cos( ) = -1/2 ororor cos( ) = 1/3 a. ( )=180-60 or ( )=180+60 or ( )=70.5 or ( )=360-70.5 a. ( ) = 120 oorr ( ) = 240 oorr ( ) = 70.5 oorr ( ) = 289.5 b. 2 - 2sin( ) = cos( ) b. 2[sin( ) + cos( )] - 2sin( ) = cos( ) b. 2sin( ) + 2cos( ) - 2sin( ) = cos( ) b. 2cos( ) - cos( ) = 0 b. cos( ) [2cos( ) - 1] = 0 b. cos( ) = 0 ororor cos( ) = b. ( ) = 90 oorr ( ) = 270 oorr ( ) = 60o oorr ( ) = 360-60 b. ( ) = 90 oorr ( ) = 270 oorr ( ) = 60o oorr ( ) = 300 =
1a. 2cos(180+x) = 2cos(180-x) 1b. 0 2. a. 2 b. 3
4 c. 25.6degree d. 205.6
334.4 3. a43.67degree
316.32 degree b. 谂紧
∂
( )内的是什么？!