有关于cos和sin的问题 生活中有需要用到SIN、COS的事吗？
sin\u4e0ecos\u7684\u5173\u7cfb1\u3001\u5012\u6570\u5173\u7cfb\uff1a
sin\u03b1 \u00b7csc\u03b1\uff1d1
tan\u03b1 \u00b7cot\u03b1\uff1d1
cos\u03b1 \u00b7sec\u03b1\uff1d1
2\u3001\u5546\u7684\u5173\u7cfb
sin\u03b1/cos\u03b1\uff1dtan\u03b1\uff1dsec\u03b1/csc\u03b1
cos\u03b1/sin\u03b1\uff1dcot\u03b1\uff1dcsc\u03b1/sec\u03b1
3\u3001sin²\u03b1\uff0bcos²\u03b1\uff1d1
1\uff0btan²\u03b1\uff1dsec²\u03b1
1\uff0bcot²\u03b1\uff1dcsc²\u03b1
\u6269\u5c55\u8d44\u6599\uff1a
\u5e38\u7528\u4e09\u89d2\u51fd\u6570
1\u3001\u4e07\u80fd\u516c\u5f0f
sina=[2tan\uff08a/2\uff09]/[1+tan²\uff08a/2\uff09]
cosa=[1-tan²\uff08a/2\uff09]/[1+tan²\uff08a/2\uff09]
tana=[2tan\uff08a/2\uff09]/[1-tan²\uff08a/2\uff09]
2\u3001\u964d\u5e42\u516c\u5f0f
sin²\u03b1=[1-cos\uff082\u03b1\uff09]/2
cos²\u03b1=[1+cos\uff082\u03b1\uff09]/2
tan²\u03b1=[1-cos\uff082\u03b1\uff09]/[1+cos\uff082\u03b1\uff09]
3\u3001\u4e09\u89d2\u548c
sin\uff08\u03b1+\u03b2+\u03b3\uff09=sin\u03b1\u00b7cos\u03b2\u00b7cos\u03b3+cos\u03b1\u00b7sin\u03b2\u00b7cos\u03b3+cos\u03b1\u00b7cos\u03b2\u00b7sin\u03b3-sin\u03b1\u00b7sin\u03b2\u00b7sin\u03b3
cos\uff08\u03b1+\u03b2+\u03b3\uff09=cos\u03b1\u00b7cos\u03b2\u00b7cos\u03b3-cos\u03b1\u00b7sin\u03b2\u00b7sin\u03b3-sin\u03b1\u00b7cos\u03b2\u00b7sin\u03b3-sin\u03b1\u00b7sin\u03b2\u00b7cos\u03b3
tan\uff08\u03b1+\u03b2+\u03b3\uff09=\uff08tan\u03b1+tan\u03b2+tan\u03b3-tan\u03b1\u00b7tan\u03b2\u00b7tan\u03b3\uff09\u00f7\uff081-tan\u03b1\u00b7tan\u03b2-tan\u03b2\u00b7tan\u03b3-tan\u03b3\u00b7tan\u03b1\uff09
\u8fd9\u91cc\u8bf4\u4e0b\u6211\u5de5\u4f5c\u76f8\u5173\u7684\u2014\u2014\u6e38\u620f\u5236\u4f5c\u3002
\u5728\u6e38\u620f\u5236\u4f5c\u4e2d\uff0c\u7269\u4f53\u7684\u79fb\u52a8\u4e0d\u4e00\u5b9a\u90fd\u662f\u5300\u901f\u7684\uff0c\u50cf\u8f6c\u76d8\u7684\u8f6c\u52a8\uff0c\u662f\u6709\u4e00\u4e2a\u6e10\u53d8\u52a0\u901f-\u300b\u6e10\u53d8\u51cf\u901f\u7684\u8fc7\u7a0b\u7684\uff0c\u5982\u679c\u7ed9\u4e00\u4e2a\u5300\u901f\u8fd0\u52a8\u52a0\u4e0aSIN\u3001COS\u7684\u7cfb\u6570\u52a0\u4e58\uff0c\u5c31\u53ef\u4ee5\u5b9e\u73b0\u7c7b\u4f3c\u6548\u679c\u3002\u5728\u4e00\u4e9b\u5f15\u64ce\u4e2d\uff0c\u4e5f\u4f1a\u81ea\u5e26\u8fd9\u79cd\u6548\u679c\uff0c\u50cfSinEaseIn\u3001SinEaseOut\uff08Sin\u7f13\u52a8\u8fdb/\u51fa\uff09\u3002
\u5176\u5b9e\u8fd9\u4e9b\u51fd\u6570\u90fd\u975e\u5e38\u6709\u7528\uff0c\u4e0d\u8981\u5c0f\u770b\u4e86\u5b83\u4eec\u3002
cos0=1 sin0=0
cos30°=√3/2 sin30°=1/2
cos60°=1/2 sin60°=√3/2
cos90°=0 sin90°=1
cos180°=-1 sin180°=0
很抱歉,这两个我忘记了cos∞=？ sin∞=?
1.诱导公式
sin(-a)=-sin(a)
cos(-a)=cos(a)
sin(π2-a)=cos(a)
cos(π2-a)=sin(a)
sin(π2+a)=cos(a)
cos(π2+a)=-sin(a)
sin(π-a)=sin(a)
cos(π-a)=-cos(a)
sin(π+a)=-sin(a)
cos(π+a)=-cos(a)
2.两角和与差的三角函数
sin(a+b)=sin(a)cos(b)+cos(α)sin(b)
cos(a+b)=cos(a)cos(b)-sin(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)
tan(a+b)=tan(a)+tan(b)1-tan(a)tan(b)
tan(a-b)=tan(a)-tan(b)1+tan(a)tan(b)
3.和差化积公式
sin(a)+sin(b)=2sin(a+b2)cos(a-b2)
sin(a)−sin(b)=2cos(a+b2)sin(a-b2)
cos(a)+cos(b)=2cos(a+b2)cos(a-b2)
cos(a)-cos(b)=-2sin(a+b2)sin(a-b2)
4.二倍角公式
sin(2a)=2sin(a)cos(b)
cos(2a)=cos2(a)-sin2(a)=2cos2(a)-1=1-2sin2(a)
5.半角公式
sin2(a2)=1-cos(a)2
cos2(a2)=1+cos(a)2
tan(a2)=1-cos(a)sin(a)=sina1+cos(a)
6.万能公式
sin(a)=2tan(a2)1+tan2(a2)
cos(a)=1-tan2(a2)1+tan2(a2)
tan(a)=2tan(a2)1-tan2(a2)
7.其它公式(推导出来的 )
a⋅sin(a)+b⋅cos(a)=a2+b2sin(a+c) 其中 tan(c)=ba
a⋅sin(a)+b⋅cos(a)=a2+b2cos(a-c) 其中 tan(c)=ab
1+sin(a)=(sin(a2)+cos(a2))2
1-sin(a)=(sin(a2)-cos(a2))2
希望对你有所帮助
呵呵,7点半告诉你,我先思考一下
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