a) Express $\left( {\surd 6} \right)\cos \theta + \left( {\surd 10} \right)\sin \theta $ in the form $R\cos \left( {\theta - \alpha } \right)$, where $R \gt 0$ and ${0^ \circ } \lt \alpha \lt {90^ \circ }$. Give the value of $\alpha $ correct to 2 decimal places.
b) Hence, in each of the following cases, find the smallest positive angle $\theta $ which satisfies the equation
(i) $\left( {\surd 6} \right)\cos \theta + \left( {\surd 10} \right)\sin \theta = - 4$,
(ii) $\left( {\surd 6} \right)\cos \frac{1}{2}\theta + \left( {\surd 10} \right)\sin \frac{1}{2}\theta = 3$.
پاسخ تشریحی :
تحلیل ویدئویی تست
تحلیل ویدئویی برای این تست ثبت نشده است!