Монгол Бодлогын Сан

Заавар: $$\begin{align*} \dfrac{\sin\alpha}{\sin^3\alpha+\cos^3\alpha}&=\dfrac{\sin\alpha(\sin^2\alpha+\cos^2\alpha)}{\sin^3\alpha+\cos^3\alpha}=\dfrac{\sin^3\alpha+\cos^2\alpha\cdot\sin\alpha}{\sin^3\alpha+\cos^3\alpha}\\ &=\dfrac{\dfrac{\sin^3\alpha+\cos^2\alpha\cdot\sin\alpha}{\cos^3x}}{\dfrac{\sin^3\alpha+\cos^3\alpha}{\cos^3x}}=\dfrac{\tg^3\alpha+\tg\alpha}{\tg^3\alpha+1} \end{align*}$$ болохыг ашигла.

Бодолт: $$\dfrac{\sin\alpha}{\sin^3\alpha+\cos^3\alpha}=\dfrac{\tg^3\alpha+\tg\alpha}{\tg^3\alpha+1}=\dfrac{3^3+3}{3^3+1}=\dfrac{30}{28}=\dfrac{15}{14}.$$