解答
求解 t,v=311cos(30t+30∘)v
解答
t=15180∘n−1∘+301.56758…,t=12∘−1∘+15180∘n−301.56758…
+1
弧度
t=−180π+301.56758…+15πn,t=15π−180π−301.56758…+15πn求解步骤
v=311cos(30t+30∘)v
交换两边311cos(30t+6π)v=v
两边除以 311v;v=0
311cos(30t+6π)v=v
两边除以 311v;v=0311v311cos(30t+6π)v=311vv;v=0
化简cos(30t+6π)=3111;v=0
cos(30t+6π)=3111;v=0
使用反三角函数性质
cos(30t+30∘)=3111
cos(30t+30∘)=3111的通解cos(x)=a⇒x=arccos(a)+360∘n,x=360∘−arccos(a)+360∘n30t+30∘=arccos(3111)+360∘n,30t+30∘=360∘−arccos(3111)+360∘n
30t+30∘=arccos(3111)+360∘n,30t+30∘=360∘−arccos(3111)+360∘n
解 30t+30∘=arccos(3111)+360∘n:t=15180∘n−1∘+30arccos(3111)
30t+30∘=arccos(3111)+360∘n
将 30∘到右边
30t+30∘=arccos(3111)+360∘n
两边减去 30∘30t+30∘−30∘=arccos(3111)+360∘n−30∘
化简30t=arccos(3111)+360∘n−30∘
30t=arccos(3111)+360∘n−30∘
两边除以 30
30t=arccos(3111)+360∘n−30∘
两边除以 303030t=30arccos(3111)+30360∘n−3030∘
化简
3030t=30arccos(3111)+30360∘n−3030∘
化简 3030t:t
3030t
数字相除:3030=1=t
化简 30arccos(3111)+30360∘n−3030∘:15180∘n−1∘+30arccos(3111)
30arccos(3111)+30360∘n−3030∘
对同类项分组=30360∘n−3030∘+30arccos(3111)
30360∘n=15180∘n
30360∘n
约分:2=15180∘n
3030∘=1∘
3030∘
使用分式法则: acb=c⋅ab=6⋅30180∘
数字相乘:6⋅30=180=1∘
=15180∘n−1∘+30arccos(3111)
t=15180∘n−1∘+30arccos(3111)
t=15180∘n−1∘+30arccos(3111)
t=15180∘n−1∘+30arccos(3111)
解 30t+30∘=360∘−arccos(3111)+360∘n:t=12∘−1∘+15180∘n−30arccos(3111)
30t+30∘=360∘−arccos(3111)+360∘n
将 30∘到右边
30t+30∘=360∘−arccos(3111)+360∘n
两边减去 30∘30t+30∘−30∘=360∘−arccos(3111)+360∘n−30∘
化简30t=360∘−arccos(3111)+360∘n−30∘
30t=360∘−arccos(3111)+360∘n−30∘
两边除以 30
30t=360∘−arccos(3111)+360∘n−30∘
两边除以 303030t=12∘−30arccos(3111)+30360∘n−3030∘
化简
3030t=12∘−30arccos(3111)+30360∘n−3030∘
化简 3030t:t
3030t
数字相除:3030=1=t
化简 12∘−30arccos(3111)+30360∘n−3030∘:12∘−1∘+15180∘n−30arccos(3111)
12∘−30arccos(3111)+30360∘n−3030∘
对同类项分组=12∘+30360∘n−3030∘−30arccos(3111)
12∘=12∘
12∘
约分:2=12∘
30360∘n=15180∘n
30360∘n
约分:2=15180∘n
3030∘=1∘
3030∘
使用分式法则: acb=c⋅ab=6⋅30180∘
数字相乘:6⋅30=180=1∘
=12∘+15180∘n−1∘−30arccos(3111)
对同类项分组=12∘−1∘+15180∘n−30arccos(3111)
t=12∘−1∘+15180∘n−30arccos(3111)
t=12∘−1∘+15180∘n−30arccos(3111)
t=12∘−1∘+15180∘n−30arccos(3111)
t=15180∘n−1∘+30arccos(3111),t=12∘−1∘+15180∘n−30arccos(3111)
以小数形式表示解t=15180∘n−1∘+301.56758…,t=12∘−1∘+15180∘n−301.56758…