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urp:trig [2021-10-15]
nerf_herder
urp:trig [2021-10-21] (current)
nerf_herder
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 transformations of sine or cosine function: ​ transformations of sine or cosine function: ​
- y = a * sin(k(x c)) + d+ y = a * sin(b(x c)) + d
    
-a = amplitude, -c = phase shift, d = vertical shift, 2pi/k = period +{{:​urp:​sinewave.jpg?​418|Sine Wave Transformations}}
-for tan, the period is pi/k+
  
 +(Graphics from www.Desmos.com,​ labeling was added) a = amplitude, c = phase shift, d = vertical shift, 2π/b = period
 +(for tan the period is π/b)
 +
 +==== Sin/Cos table ====
 +
 +^  Radians ​   ^  Degrees ​ ^  Cos  ^  Sin  ^
 +|   ​**0** ​    ​| ​  ​0 ​     |   ​1 ​   |   ​0 ​  |
 +|   ​π/​6 ​      ​| ​  ​30 ​    ​| ​ √3/​2 ​ |  1/2  |
 +|   ​π/​4 ​      ​| ​  ​45 ​    ​| ​ √2/​2 ​ |  √2/​2 ​ |
 +|   ​π/​3 ​      ​| ​  ​60 ​    ​| ​ 1/2  |  √3/​2 ​ |
 +|   ​**π/​2** ​  ​| ​  ​90 ​    ​| ​  ​0 ​  ​| ​  ​1 ​  |
 +|   ​2π/​3 ​     |   ​120 ​   |  -1/2  |  √3/​2 ​ |
 +|   ​3π/​4 ​     |   ​135 ​   |  -√2/​2 ​ |  √2/​2 ​ |
 +|   ​5π/​6 ​     |   ​150 ​   |  -√3/​2 ​ |  1/2  |
 +|   ​**π** ​      ​| ​  ​180 ​   |  -1   ​| ​  ​0 ​  |
 +|  -5π/6, 7π/6  |   ​210 ​   |  -√3/​2 ​ |  -1/2  |
 +|  -3π/4, 5π/4  |   ​225 ​   |  -√2/​2 ​ |  -√2/​2 ​ |
 +|  -2π/3, 4π/3  |   ​240 ​   |  -1/2  |  -√3/​2 ​ |
 +|  **-π/2, 3π/​2** ​ |   ​270 ​   |   ​0 ​   |  -1   |
 +|  -π/3, 5π/3   ​| ​  ​300 ​   |  1/2   ​| ​ -√3/​2 ​ |
 +|  -π/4, 7π/4   ​| ​  ​315 ​   |  √2/​2 ​ |  -√2/​2 ​ |
 +|  -π/6, 11π/​6 ​ |   ​330 ​   |  √3/​2 ​ |  -1/2  |
 +|  **0, 2π**      |   ​360 ​   |   ​1 ​  ​| ​  ​0 ​  |
 +
 +==== Conversion Theorems ====
 double angle: 2θ double angle: 2θ
   sin(2θ) = 2sin(θ)cos(θ)   sin(2θ) = 2sin(θ)cos(θ)
-  cos(2θ) = cos^2(θ) - sin^2(θ) +  cos(2θ) = cos²(θ) - sin²(θ) 
-              = 2*cos^2(θ) - 1 +          = 2*cos²(θ) - 1 
-              = 1 - 2*sin^2(θ)+          = 1 - 2*sin²(θ) 
 negative angles: negative angles:
   sin(-θ) = -sin(θ)   sin(-θ) = -sin(θ)
-  cos(-θ) = cos(θ)  ​=> tan(-θ) = -tan(θ)+  cos(-θ) = cos(θ) 
 +  ​tan(-θ) = -tan(θ)
  
 additive, subtractive:​ additive, subtractive:​
- sin(a+b) = sin(a)cos(b) + cos(a)sin(b) +  ​sin(a+b) = sin(a)cos(b) + cos(a)sin(b) 
- ​cos(a+b) = cos(a)cos(b) - sin(a)sin(b) +  cos(a+b) = cos(a)cos(b) - sin(a)sin(b) 
- ​sin(a-b) = sin(a)cos(b) - cos(a)sin(b) +  sin(a-b) = sin(a)cos(b) - cos(a)sin(b) 
- ​cos(a-b) = cos(a)cos(b) + sin(a)sin(b)+  cos(a-b) = cos(a)cos(b) + sin(a)sin(b)
  
 complements:​ complements:​
- sin(θ) = cos(pi/2 - θ) +  ​sin(θ) = cos(π/2 - θ) 
- ​cos(θ) = sin(pi/2 - θ)+  cos(θ) = sin(π/2 - θ)
  
 === See also === === See also ===
urp/trig.1634318886.txt.gz · Last modified: 2021-10-15 by nerf_herder