Toán Lớp 11: cos (2.13x – 60 độ) = 1/2
gải pt hộ mk vs ak
Leave a reply
Register Now
Login
Lost Password
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Toán Lớp 11: cos (2.13x – 60 độ) = 1/2
gải pt hộ mk vs ak
Comments ( 1 )
x = \dfrac{{{{60}^0}}}{{13}} + \dfrac{{k{{.180}^0}}}{{13}}\\
x = \dfrac{{k{{.180}^0}}}{{13}}
\end{array} \right.\left( {k \in Z} \right)$
\cos \left( {2.13x – {{60}^0}} \right) = \dfrac{1}{2}\\
\Leftrightarrow \left[ \begin{array}{l}
26x – {60^0} = {60^0} + k{.360^0}\\
26x – {60^0} = – {60^0} + k{.360^0}
\end{array} \right.\left( {k \in Z} \right)\\
\Leftrightarrow \left[ \begin{array}{l}
26x = {120^0} + k{.360^0}\\
26x = k{.360^0}
\end{array} \right.\left( {k \in Z} \right)\\
\Leftrightarrow \left[ \begin{array}{l}
x = \dfrac{{{{60}^0}}}{{13}} + \dfrac{{k{{.180}^0}}}{{13}}\\
x = \dfrac{{k{{.180}^0}}}{{13}}
\end{array} \right.\left( {k \in Z} \right)\\
Vay\,\left[ \begin{array}{l}
x = \dfrac{{{{60}^0}}}{{13}} + \dfrac{{k{{.180}^0}}}{{13}}\\
x = \dfrac{{k{{.180}^0}}}{{13}}
\end{array} \right.\left( {k \in Z} \right)
\end{array}$