[ti:Trigonometric Functions 三角函数之歌(Cover 映射者)] [ar:Various Artists] [al:] [by:] [offset:0] [00:00.00]Trigonometric Functions - Various Artists [00:03.37]原唱:映射者/天儿 [00:05.13]后期:昔染 [00:06.22]视频:讲不清 [00:10.53]When you first study math about 1234 [00:12.96]First study equation about xyzt [00:14.95]It will help you to think in a logical way [00:17.02]When you sing sine cosine tangent [00:19.28]Sine cosine tangent cotangent [00:21.47]Sine cosine secant cosecant [00:23.59]Let's sing a song about trig-functions [00:25.73]sin(2π+α)=sinα [00:27.68]cos(2π+α)=cosα [00:30.02]tan(2π+α)=tanα [00:31.96]Which is induction formula1 and induction formula 2 [00:34.35]sin(π+α)=-sinα [00:36.34]cos(π+α)=-cosα [00:38.62]tan(π+α)=tanα [00:40.68]sin(π-α)=sinα [00:42.71]cos(π-α)=-cosα [00:44.78]tan(π-α)=-tanα [00:47.37]These are all those"name do not change" [00:49.30]As pi goes to half pi the difference shall be huge [00:51.58]sin(π/2+α)=cosα [00:53.35]sin(π/2-α)=cosα [00:55.55]cos(π/2+α)=-sinα [00:57.70]cos(π/2-α)=sinα [00:59.89]tan(π/2+α)=-cotα [01:02.02]tan(π/2-α)=cotα [01:08.65]That is to say the odds will change evens are conserved [01:12.67]The notations that they get depend on where they are [01:17.00]But no matter where you are [01:19.27]I've gotta say that [01:21.48]If you were my sine curve I'd be your cosine curve [01:25.77]I'll be your derivative you'll be my negative one [01:30.01]As you change you amplitude I change my phase [01:34.08]We can oscillate freely in the external space [01:38.58]As we change our period and costant at hand [01:42.76]We travel from the origin to infinity [01:46.93]It's you sine and you cosine [01:51.41]Who make charming music around the world [01:55.48]It's you tangent cotangent [01:59.82]Who proclaim the true meaning of centrosymmetry [02:47.26]You wanna measure width of a river height of a tower [02:49.21]You scratch your head which cost you more than an hour [02:51.41]You don't need to ask any"gods" or" master" for help [02:53.41]This group of formulas are gonna help you solve [02:55.76]sin(α+β)=sinα•cosβ+cosα•sinβ [02:58.99]cos(α+β)=cosα•cosβ-sinα•sinβ [03:02.21]tan(α+β)=(tanα+tanβ)/(1-tanα•tanβ) [03:06.44]sin(α-β)=sinα•cosβ-cosα•sinβ [03:09.68]cos(α-β)=cosα•cosβ+sinα•sinβ [03:12.85]tan(α-β)=(tanα-tanβ)/(1+tanα•tanβ) [03:17.14]As you come across a right triangle you feel easy to solve [03:20.17]But an obtuse triange gonna make you feel confused [03:22.59]Don't worry about what you do [03:23.65]There are always means to solve [03:24.53]As long as you master the sine cosine law [03:30.12]At this moment I've got nothing to say [03:34.40]As trig-functions rain down upon me [03:38.68]At this moment I've got nothing to say [03:42.85]Let's sing a song about trig-functions [03:47.22]Long live the trigonometric functions