用C(α+β)推导公式cos（180°-α）＝-cosα
cos\u03b1+cos(180-\u03b1)=?\u63a8\u5bfc\u8fc7\u7a0b\u53e3\u8bc0\u662f\u8fd9\u6837\u7684\uff1a90\u5ea6\u65f6\u53d8\u51fd\u6570\u7b26\u53f7\uff0c180\u5ea6\u65f6\u4e0d\u53d8\u51fd\u6570\u7b26\u53f7
\u03b1\u6c38\u8fdc\u5047\u5b9a\u7684\u8ba4\u4e3a\u662f\u5c0f\u4e8e90\u5ea6\u7684\uff0c\u770b\u5b83\u548c90,180\u76f8\u52a0\u51cf\u540e\u5728\u539f\u4e09\u89d2\u51fd\u6570\u4e2d\u7684\u7b26\u53f7\uff0c\u5b9a\u51fa\u7b26\u53f7\u3002
\u5982sin(\u03b1+90)=cos\u03b1,sin(90-\u03b1)=cos\u03b1
sin(180+\u03b1)=-sin\u03b1
\u539f\u9898:
cos\u03b1+cos(180-\u03b1)=cos\u03b1-cos\u03b1=0
\u8fd9\u4e2a\u53eb\u6b27\u62c9\u516c\u5f0f\uff0c\u5728\u9ad8\u7b49\u6570\u5b66\u4e2d\u7684\u7ea7\u6570\u90e8\u5206\uff0c\u4f1a\u8bb2\u5230\u3002\u5b83\u7684\u8bc1\u660e\u662f\u57fa\u4e8e\u6cf0\u52d2\u5c55\u5f00
\u5176\u4e2d
e^x=1+x+x^2/2!+\u2026\u2026+x^n/n!+\u2026\u2026
\u82e5\u628aix\u770b\u6210x\u5219
e^(ix)=1+ix-x^2/2!-ix^3/3!+x^4/4!+\u2026\u2026
\u800c
cosx=1-x^2/2++x^4/4!+\u2026\u2026+(-1)^n*x^(2n)/(2n)!+\u2026\u2026
sinx=x-x^3/3!+x^5/5!+\u2026\u2026+(-1)^(n-1)*x^(2n-1)/(2n-1)!+\u2026\u2026
\u6bd4\u8f83\u4e00\u4e0b
e^(ix)\u9a6c\u4e0a\u5c31\u6709e^(ix)=cos(x)+iSin(x)
绛旓細鏍规嵁cos浣欏鸡瀹氱悊鍏紡锛歝² = a² + b² - 2ab路cos(C)浠ｅ叆宸茬煡鏁版嵁锛屽緱鍒帮細c² = 5² + 7² - 2脳5脳7脳cos(30掳)鍖栫畝璁＄畻锛歝² = 25 + 49 - 70脳cos(30掳)浣跨敤涓夎鍑芥暟琛ㄦ煡鎵綾os(30掳) 鈮 0.866 鍒欙細c² = 25 + 49 - 70脳0...
绛旓細cos(2蟺-a)=cos(2蟺)cosa+sin(2蟺)sina=cosa
绛旓細cos(2蟺-a)=cos2蟺cosa+sin2蟺sina=cosa+0=cosa
绛旓細sin锛3蟺/2-伪锛= sin3蟺/2 cos伪- cos3蟺/2 sin伪=-cos伪
绛旓細鍏紡Cos(伪+尾锛=cosacosb-sinasinb Cos(伪-尾锛=cosacosb+sinasinb cos(2蟺-伪锛=cos2蟺cosa+sin2蟺sina cos2蟺=1 sin2蟺=0 =cosa
绛旓細鍙互
绛旓細涓よ鍜岀殑浣欏鸡鍏紡锛cos锛埼 尾锛=cos伪cos尾-sin伪sin尾锛(鎬濊矾:鍦ㄧ洿瑙掑潗鏍囩郴鐨勫崟浣嶅渾涓紝鏍规嵁涓ょ偣闂寸殑璺濈鍏紡鏉鎺ㄥ)浣溾垹AOD=伪锛屸垹BOD=-尾锛屸垹AOC=尾锛屸垹DOC=尾 伪銆傚垯B锛坈os尾锛-sin尾锛夛紱D锛1锛0锛夛紱A锛坈os伪锛宻in伪锛夛紱C[cos锛埼 尾锛夛紝sin锛埼 尾锛塢銆傗埖 OA=OB=OC=OD=1 ...
绛旓細cos锛埼-尾锛=cos伪cos尾+sin伪sin尾锛宑os锛埼+尾锛=cos伪cos尾-sin伪sin尾锛宻in锛埼-尾锛=sin伪cos尾-cos伪sin尾锛宻in锛埼+尾锛=sin伪cos尾+cos伪sin尾銆備綑寮﹀畾鐞嗕綔涓哄叧浜庝笁瑙掑舰杈硅鍏崇郴鐨勯噸瑕佸畾鐞嗕箣涓锛岃瀹氱悊鍖呭惈涓夎褰换涓杈圭殑骞虫柟绛変簬鍏朵粬涓よ竟骞虫柟鍜屽噺鍘昏繖涓よ竟涓庡畠浠す瑙掔殑浣欏鸡鐨勭Н鐨勪袱鍊...
绛旓細cos锛埼-尾锛=cos伪cos尾+sin伪sin尾 cos锛埼+尾锛=cos伪cos尾-sin伪sin尾 sin锛埼-尾锛=sin伪cos尾-cos伪sin尾 sin 锛埼+尾锛=sin伪cos尾+cos伪sin尾
绛旓細涓よ鍜屼笌宸殑姝ｅ鸡銆佷綑寮︺佹鍒囧叕寮忎袱瑙掑樊鐨勪綑寮鍏紡cos()coscossinsin1涓よ鍜岀殑浣欏鸡鍏紡鎺ㄥcos()coscossinsin灏嗘浛鎹负cos()cos(())coscos()sinsin()coscossinsin2涓よ鍜岀殑浣欏鸡鍏紡cos()coscossinsin涓婅堪鍏紡绠璁颁负C鍏紡涓殑伪銆尾涓轰换鎰忚銆3涓よ鍜屼笌宸殑浣欏鸡鍏紡锛歝os()coscosmsinsin4涓よ鍜岀殑...
