解答
2sin(x+60∘)=cos(x+30∘)
解答
x=150∘+180∘n
+1
弧度
x=65π+πn求解步骤
2sin(x+60∘)=cos(x+30∘)
使用三角恒等式改写
2sin(x+60∘)=cos(x+30∘)
使用三角恒等式改写
sin(x+60∘)
使用角和恒等式: sin(s+t)=sin(s)cos(t)+cos(s)sin(t)=sin(x)cos(60∘)+cos(x)sin(60∘)
化简 sin(x)cos(60∘)+cos(x)sin(60∘):21sin(x)+23cos(x)
sin(x)cos(60∘)+cos(x)sin(60∘)
化简 cos(60∘):21
cos(60∘)
使用以下普通恒等式:cos(60∘)=21
cos(x) 周期表(周期为 360∘n):
x030∘45∘60∘90∘120∘135∘150∘cos(x)12322210−21−22−23x180∘210∘225∘240∘270∘300∘315∘330∘cos(x)−1−23−22−210212223
=21=21sin(x)+sin(60∘)cos(x)
化简 sin(60∘):23
sin(60∘)
使用以下普通恒等式:sin(60∘)=23
sin(x) 周期表(周期为 360∘n"):
x030∘45∘60∘90∘120∘135∘150∘sin(x)02122231232221x180∘210∘225∘240∘270∘300∘315∘330∘sin(x)0−21−22−23−1−23−22−21
=23=21sin(x)+23cos(x)
=21sin(x)+23cos(x)
使用角和恒等式: cos(s+t)=cos(s)cos(t)−sin(s)sin(t)=cos(x)cos(30∘)−sin(x)sin(30∘)
化简 cos(x)cos(30∘)−sin(x)sin(30∘):23cos(x)−21sin(x)
cos(x)cos(30∘)−sin(x)sin(30∘)
化简 cos(30∘):23
cos(30∘)
使用以下普通恒等式:cos(30∘)=23
cos(x) 周期表(周期为 360∘n):
x030∘45∘60∘90∘120∘135∘150∘cos(x)12322210−21−22−23x180∘210∘225∘240∘270∘300∘315∘330∘cos(x)−1−23−22−210212223
=23=23cos(x)−sin(30∘)sin(x)
化简 sin(30∘):21
sin(30∘)
使用以下普通恒等式:sin(30∘)=21
sin(x) 周期表(周期为 360∘n"):
x030∘45∘60∘90∘120∘135∘150∘sin(x)02122231232221x180∘210∘225∘240∘270∘300∘315∘330∘sin(x)0−21−22−23−1−23−22−21
=21=23cos(x)−21sin(x)
=23cos(x)−21sin(x)
2(21sin(x)+23cos(x))=23cos(x)−21sin(x)
化简 2(21sin(x)+23cos(x)):sin(x)+3cos(x)
2(21sin(x)+23cos(x))
使用分配律: a(b+c)=ab+aca=2,b=21sin(x),c=23cos(x)=2⋅21sin(x)+2⋅23cos(x)
化简 2⋅21sin(x)+2⋅23cos(x):sin(x)+3cos(x)
2⋅21sin(x)+2⋅23cos(x)
2⋅21sin(x)=sin(x)
2⋅21sin(x)
分式相乘: a⋅cb=ca⋅b=21⋅2sin(x)
约分:2=sin(x)⋅1
乘以:sin(x)⋅1=sin(x)=sin(x)
2⋅23cos(x)=3cos(x)
2⋅23cos(x)
分式相乘: a⋅cb=ca⋅b=223cos(x)
约分:2=cos(x)3
=sin(x)+3cos(x)
=sin(x)+3cos(x)
sin(x)+3cos(x)=23cos(x)−21sin(x)
sin(x)+3cos(x)=23cos(x)−21sin(x)
两边减去 23cos(x)−21sin(x)23sin(x)−23cos(x)+3cos(x)=0
化简 23sin(x)−23cos(x)+3cos(x):23sin(x)+3cos(x)
23sin(x)−23cos(x)+3cos(x)
乘 23sin(x):23sin(x)
23sin(x)
分式相乘: a⋅cb=ca⋅b=23sin(x)
=23sin(x)−23cos(x)+3cos(x)
乘 23cos(x):23cos(x)
23cos(x)
分式相乘: a⋅cb=ca⋅b=23cos(x)
=23sin(x)−23cos(x)+3cos(x)
合并分式 23sin(x)−23cos(x):23sin(x)−3cos(x)
使用法则 ca±cb=ca±b=23sin(x)−3cos(x)
=23sin(x)−3cos(x)+3cos(x)
将项转换为分式: 3cos(x)=23cos(x)2=23sin(x)−3cos(x)+23cos(x)⋅2
因为分母相等,所以合并分式: ca±cb=ca±b=23sin(x)−3cos(x)+3cos(x)⋅2
同类项相加:−3cos(x)+23cos(x)=3cos(x)=23sin(x)+3cos(x)
23sin(x)+3cos(x)=0
g(x)f(x)=0⇒f(x)=03sin(x)+3cos(x)=0
使用三角恒等式改写
3sin(x)+3cos(x)=0
在两边除以 cos(x),cos(x)=0cos(x)3sin(x)+3cos(x)=cos(x)0
化简cos(x)3sin(x)+3=0
使用基本三角恒等式: cos(x)sin(x)=tan(x)3tan(x)+3=0
3tan(x)+3=0
将 3到右边
3tan(x)+3=0
两边减去 33tan(x)+3−3=0−3
化简3tan(x)=−3
3tan(x)=−3
两边除以 3
3tan(x)=−3
两边除以 333tan(x)=3−3
化简tan(x)=−33
tan(x)=−33
tan(x)=−33的通解
tan(x) 周期表(周期为 180∘n):
x030∘45∘60∘90∘120∘135∘150∘tan(x)03313±∞−3−1−33
x=150∘+180∘n
x=150∘+180∘n