sin2x等于多少？ sin2x等于多少?
sin2x\u7b49\u4e8e\u591a\u5c11\uff1fsin2x=2sinxcosx,
\u8fd9\u5176\u5b9e\u662f\u7531\u4e24\u89d2\u548c\u7684\u6b63\u5f26\u516c\u5f0f
sin\uff08x+y\uff09=sinxcosy+cosxsiny \u5f97\u5230\u3002
\u6b64\u5916\uff0c\u8fd8\u6709\u51e0\u4e2a\u4e09\u89d2\u6052\u7b49\u5f0f\uff1a
cos\uff08x+y\uff09=cosxcosy-sinxsiny
cos\uff08x-y\uff09=cosxcosy+sinxsiny
sin\uff08x-y\uff09=sinxcosy-cosxsiny
tan\uff08x+y\uff09=\uff08tanx+tany\uff09/\uff081-tanxtany\uff09
tan\uff08x-y\uff09=\uff08tanx-tany\uff09/\uff081+tanxtany\uff09
\u60f3\u63a8\u5bfc\u51fa\u5404\u79cd\u4e8c\u500d\u89d2\u516c\u5f0f\uff0c
\u53ea\u9700\u5c06\u548c\u89d2\u516c\u5f0f\u4e2d\u7684y\u66ff\u6362\u4e3ax\u5373\u53ef\u3002
*\u6ce8\u610f\uff1a\u4e24\u89d2\u548c\u5dee\u7684\u6b63\u5207\u516c\u5f0f\u5fc5\u987b\u5728\u7b49\u5f0f\u4e24\u8fb9\u90fd\u6709\u610f\u4e49\u65f6\u65b9\u53ef\u6210\u7acb\u3002
sin2x=2sinxcosx
\u8fd9\u5176\u5b9e\u662f\u7531\u4e24\u89d2\u548c\u7684\u6b63\u5f26\u516c\u5f0f\uff0c\u7531sin\uff08x+y\uff09=sinxcosy+cosxsiny \u5f97\u5230\u3002
\u6b64\u5916,\u8fd8\u6709\u51e0\u4e2a\u4e09\u89d2\u6052\u7b49\u5f0f\uff1a
cos\uff08x-y\uff09=cosxcosy+sinxsiny
sin\uff08x-y\uff09=sinxcosy-cosxsiny
\u60f3\u63a8\u5bfc\u51fa\u5404\u79cd\u4e8c\u500d\u89d2\u516c\u5f0f\uff0c\u53ea\u9700\u5c06\u548c\u89d2\u516c\u5f0f\u4e2d\u7684y\u66ff\u6362\u4e3ax\u5373\u53ef\u3002
\u6ce8\u610f\uff1a\u4e24\u89d2\u548c\u5dee\u7684\u6b63\u5207\u516c\u5f0f\u5fc5\u987b\u5728\u7b49\u5f0f\u4e24\u8fb9\u90fd\u6709\u610f\u4e49\u65f6\u65b9\u53ef\u6210\u7acb\u3002
\u6269\u5c55\u8d44\u6599\uff1a\u4e09\u89d2\u51fd\u6570\u4e2d\u5176\u4ed6\u91cd\u8981\u516c\u5f0f\u4ecb\u7ecd\u5982\u4e0b\uff1a
\u4e00\u3001\u548c\u5dee\u5316\u79ef
1\u3001sin\u03b8+sin\u03c6 = 2 sin[(\u03b8+\u03c6)/2] cos[(\u03b8-\u03c6)/2]
2\u3001sin\u03b8-sin\u03c6 = 2 cos[(\u03b8+\u03c6)/2] sin[(\u03b8-\u03c6)/2]
3\u3001cos\u03b8+cos\u03c6 = 2 cos[(\u03b8+\u03c6)/2] cos[(\u03b8-\u03c6)/2]
4\u3001cos\u03b8-cos\u03c6 = -2 sin[(\u03b8+\u03c6)/2] sin[(\u03b8-\u03c6)/2]
5\u3001tanA+tanB=sin(A+B)/cosAcosB=tan(A+B)(1-tanAtanB)
6\u3001tanA-tanB=sin(A-B)/cosAcosB=tan(A-B)(1+tanAtanB)
\u4e8c\u3001\u964d\u5e42\u516c\u5f0f
sin^2(\u03b1)=(1-cos(2\u03b1))/2=versin(2\u03b1)/2
cos^2(\u03b1)=(1+cos(2\u03b1))/2=covers(2\u03b1)/2
tan^2(\u03b1)=(1-cos(2\u03b1))/(1+cos(2\u03b1))
\u4e09\u3001n\u500d\u89d2\u516c\u5f0f
\u6839\u636e\u6b27\u62c9\u516c\u5f0f\uff08cos\u03b8+isin\u03b8\uff09^n=cosn\u03b8+isinn\u03b8
\u5c06\u5de6\u8fb9\u7528\u4e8c\u9879\u5f0f\u5b9a\u7406\u5c55\u5f00\u5206\u522b\u6574\u7406\u5b9e\u90e8\u548c\u865a\u90e8\u53ef\u4ee5\u5f97\u5230\u4e0b\u9762\u4e24\u7ec4\u516c\u5f0f
1\u3001sin\uff08n\u03b1\uff09=ncosn-1\u03b1\u00b7sin\u03b1-C\uff08n,3\uff09cosn-3\u03b1\u00b7sin3\u03b1+C\uff08n,5\uff09cosn-5\u03b1\u00b7sin5\u03b1
2\u3001cos\uff08n\u03b1\uff09=cosn\u03b1-C\uff08n,2\uff09cosn-2\u03b1\u00b7sin2\u03b1+C\uff08n,4\uff09cosn-4\u03b1\u00b7sin4\u03b1
\u56db\u3001\u4e09\u89d2\u548c\u516c\u5f0f
1\u3001sin(\u03b1+\u03b2+\u03b3)
=sin\u03b1\u00b7cos\u03b2\u00b7cos\u03b3+cos\u03b1\u00b7sin\u03b2\u00b7cos\u03b3+cos\u03b1\u00b7cos\u03b2\u00b7sin\u03b3-sin\u03b1\u00b7sin\u03b2\u00b7sin\u03b3
2\u3001cos(\u03b1+\u03b2+\u03b3)
=cos\u03b1\u00b7cos\u03b2\u00b7cos\u03b3-cos\u03b1\u00b7sin\u03b2\u00b7sin\u03b3-sin\u03b1\u00b7cos\u03b2\u00b7sin\u03b3-sin\u03b1\u00b7sin\u03b2\u00b7cos\u03b3
3\u3001tan(\u03b1+\u03b2+\u03b3)
=(tan\u03b1+tan\u03b2+tan\u03b3-tan\u03b1\u00b7tan\u03b2\u00b7tan\u03b3)/(1-tan\u03b1\u00b7tan\u03b2-tan\u03b2\u00b7tan\u03b3-tan\u03b3\u00b7tan\u03b1)
请问X等于多少
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