sin(6π-a)等于什么
-sin(\u03c0/6-a)\u4e3a\u4ec0\u4e48\u7b49\u4e8e-a\u4e24\u4e2a\u662f\u4e0d\u76f8\u7b49\u7684\u3002
\u5982\u679c\u4e0d\u61c2\uff0c\u8bf7\u8ffd\u95ee\uff0c\u795d\u5b66\u4e60\u6109\u5feb\uff01
\u89e3\uff1a
sin(-7\u03c0\uff0f6)
=-sin(-7\u03c0/6+\u03c0)
=-sin(-\u03c0/6)
=sin(\u03c0/6)
=1/2
\u672c\u9898\u7528\u5230\u516c\u5f0f\uff1asina=-sin(\u03c0+a)
sin(-a)=-sina
=sina(2kπ-a) k=3
=sina(-a)
=-sina
-sinα
绛旓細浠sin(蟺/6-a)=sinx=1/4 鍒檆os(蟺/3-2a)=cos2x=1-2sin²x 甯﹀叆涓婂紡鍙緱 cos(蟺/3-2a)=1-2*(1/16)=7/8
绛旓細鈭sin(蟺/6-伪)=1/3 鈭碿os[2(蟺/6-伪)]=1-sin²(蟺/6-伪)=7/9 鍗砪os(蟺/3-2伪)=7/9 cos(2蟺/3+2伪)=cos[2(蟺/3+伪)]=cos[2(蟺/2-蟺/6+伪)]=cos[蟺-(蟺/3-2伪)]= -cos(蟺/3-2伪)=-7/9
绛旓細sin(2蟺-伪)绛変簬-sina銆傚垎鏋愶細sin(2蟺-伪)=sin(-a)=-sina銆傜Н鍖栧拰宸叕寮忥細sin伪路cos尾=(1/2)[sin(伪+尾)+sin(伪-尾)]cos伪路sin尾=(1/2)[sin(伪+尾)-sin(伪-尾)]cos伪路cos尾=(1/2)[cos(伪+尾)+cos(伪-尾)]sin伪路sin尾=-(1/2)[cos(伪+尾)-cos(伪-尾)]鍜屽樊...
绛旓細sin(蟺/6-伪锛=a锛屾墍浠os銆斚/2-(蟺/6-伪锛夈=a,鍗砪os锛埾/3+伪锛=a,鎵浠os銆斚-(蟺/3+伪)銆=-a,鍗砪os锛2蟺/3-伪锛=-a
绛旓細鐢卞嶈鍏紡锛2cos²(蟺/6+a/2)-1=cos(蟺/3+a)cos(蟺/3+a)=cos[蟺/2-(蟺/6-a)]=sin(蟺/6-a)=1/3 鎵浠ワ紝2cos²(蟺/6+a/2)-1=1/3 绁濅綘寮蹇冿紒甯屾湜鑳藉府鍒颁綘锛屽鏋滀笉鎳傦紝璇疯拷闂紝绁濆涔犺繘姝ワ紒O(鈭鈭)O ...
绛旓細sin(2蟺+A)=sinA銆乧os(2蟺+A)=cosA銆乼an(2蟺+A)=tanA銆乧ot(2蟺+A)=cotA sin(蟺-A)=sinA銆乧os(蟺-A)=-cosA銆乼an(蟺-A)=-tanA銆乧ot(蟺-A)=-cotA sin(蟺/2+A)=cosA銆乧os(蟺/2+A)=-sinA銆乼an(蟺/2+A)=-cotA銆乧ot(蟺/2+A)=-tanA 3銆佺壒娈婅搴︿笁瑙掑嚱鏁板 sin蟺/6=1/...
绛旓細sin(蟺/6-a)=1/3 cos(蟺/6-a)=2鏍瑰彿2/3 sina=sin(蟺/6-蟺/6+a)=1/2*2鏍瑰彿2/3-鏍瑰彿3/2*1/3 =鏍瑰彿2/3-鏍瑰彿3/6 =(2鏍瑰彿2-鏍瑰彿3)/6
绛旓細sin(a-蟺/6)=4/5 0
绛旓細鍒╃敤璇卞鍏紡锛屽師寮忓寲绠涓-cosa 鈭礳os(a-3蟺/2锛=cos[-(3蟺/2 -a)]=cos(3蟺/2 -a)=-sina=1/5 鈭磗ina=-1/5 cosa=卤鈭歔1-(sina)^2]=卤(2鈭6)/5 鈭礱鏄涓夎薄闄愯 鈭碿osa=-(2鈭6)/5 (sin(蟺-a)cos(2蟺-a)tan((3/2)蟺-a))/cos(-蟺-a) =-cosa=(2鈭6)/5 ...
绛旓細鏍瑰彿涓5锛sin(a-7蟺)=sin[(蟺+a)-8蟺]=sin(蟺+a)=-1/锛堟牴鍙蜂笅5锛塩os(蟺-a)=cos[-(蟺+a)+2蟺]=cos-(蟺+a)=cos(蟺+a)= 2/(鏍瑰彿涓5锛塩os(a-2蟺)=cos[(蟺+a)-3蟺]=-cos(蟺+a)=-2/(鏍瑰彿涓5锛塩os(a-5蟺)=cos[(蟺+a)-6蟺]=cos(蟺+a)= 2/(鏍瑰彿涓5锛
