解答
15cos(3652πt)+43=30
解答
t=2π365⋅2.61927…+365n,t=−2π365⋅2.61927…+365n
+1
度数
t=8718.00664…∘+20912.95952…∘n,t=−8718.00664…∘+20912.95952…∘n求解步骤
15cos(3652πt)+43=30
将 43到右边
15cos(3652πt)+43=30
两边减去 4315cos(3652πt)+43−43=30−43
化简15cos(3652πt)=−13
15cos(3652πt)=−13
两边除以 15
15cos(3652πt)=−13
两边除以 151515cos(3652πt)=15−13
化简cos(3652πt)=−1513
cos(3652πt)=−1513
使用反三角函数性质
cos(3652πt)=−1513
cos(3652πt)=−1513的通解cos(x)=−a⇒x=arccos(−a)+2πn,x=−arccos(−a)+2πn3652πt=arccos(−1513)+2πn,3652πt=−arccos(−1513)+2πn
3652πt=arccos(−1513)+2πn,3652πt=−arccos(−1513)+2πn
解 3652πt=arccos(−1513)+2πn:t=2π365arccos(−1513)+365n
3652πt=arccos(−1513)+2πn
在两边乘以 365
3652πt=arccos(−1513)+2πn
在两边乘以 365365⋅3652πt=365arccos(−1513)+365⋅2πn
化简
365⋅3652πt=365arccos(−1513)+365⋅2πn
化简 365⋅3652πt:2πt
365⋅3652πt
分式相乘: a⋅cb=ca⋅b=3652⋅365πt
约分:365=t⋅2π
化简 365arccos(−1513)+365⋅2πn:365arccos(−1513)+730πn
365arccos(−1513)+365⋅2πn
数字相乘:365⋅2=730=365arccos(−1513)+730πn
2πt=365arccos(−1513)+730πn
2πt=365arccos(−1513)+730πn
2πt=365arccos(−1513)+730πn
两边除以 2π
2πt=365arccos(−1513)+730πn
两边除以 2π2π2πt=2π365arccos(−1513)+2π730πn
化简
2π2πt=2π365arccos(−1513)+2π730πn
化简 2π2πt:t
2π2πt
数字相除:22=1=ππt
约分:π=t
化简 2π365arccos(−1513)+2π730πn:2π365arccos(−1513)+365n
2π365arccos(−1513)+2π730πn
消掉 2π730πn:365n
2π730πn
消掉 2π730πn:365n
2π730πn
数字相除:2730=365=π365πn
约分:π=365n
=365n
=2π365arccos(−1513)+365n
t=2π365arccos(−1513)+365n
t=2π365arccos(−1513)+365n
t=2π365arccos(−1513)+365n
解 3652πt=−arccos(−1513)+2πn:t=−2π365arccos(−1513)+365n
3652πt=−arccos(−1513)+2πn
在两边乘以 365
3652πt=−arccos(−1513)+2πn
在两边乘以 365365⋅3652πt=−365arccos(−1513)+365⋅2πn
化简
365⋅3652πt=−365arccos(−1513)+365⋅2πn
化简 365⋅3652πt:2πt
365⋅3652πt
分式相乘: a⋅cb=ca⋅b=3652⋅365πt
约分:365=t⋅2π
化简 −365arccos(−1513)+365⋅2πn:−365arccos(−1513)+730πn
−365arccos(−1513)+365⋅2πn
数字相乘:365⋅2=730=−365arccos(−1513)+730πn
2πt=−365arccos(−1513)+730πn
2πt=−365arccos(−1513)+730πn
2πt=−365arccos(−1513)+730πn
两边除以 2π
2πt=−365arccos(−1513)+730πn
两边除以 2π2π2πt=−2π365arccos(−1513)+2π730πn
化简
2π2πt=−2π365arccos(−1513)+2π730πn
化简 2π2πt:t
2π2πt
数字相除:22=1=ππt
约分:π=t
化简 −2π365arccos(−1513)+2π730πn:−2π365arccos(−1513)+365n
−2π365arccos(−1513)+2π730πn
消掉 2π730πn:365n
2π730πn
消掉 2π730πn:365n
2π730πn
数字相除:2730=365=π365πn
约分:π=365n
=365n
=−2π365arccos(−1513)+365n
t=−2π365arccos(−1513)+365n
t=−2π365arccos(−1513)+365n
t=−2π365arccos(−1513)+365n
t=2π365arccos(−1513)+365n,t=−2π365arccos(−1513)+365n
以小数形式表示解t=2π365⋅2.61927…+365n,t=−2π365⋅2.61927…+365n