Обчисліть 10sin40°sin50°/cos10°

[latex] \frac{10sin40\cdot sin 50}{cos10}= \frac{10sin40\cdot cos40}{cos10}= \frac{5sin80}{cos10}= \frac{5cos10}{cos10}=5\\\\P.S.\; \; sin \alpha =cos(90- \alpha ) [/latex]