Вычислите: 2sina+sin2a _____________ 2sina-sin2a если cos a =1/5

[latex] \frac{2sin \alpha +sin2 \alpha }{2sin \alpha -2sin2 \alpha } = \frac{2sin \alpha +2sin \alpha cos \alpha }{2sin \alpha -2sin \alpha cos \alpha } = \frac{2sin \alpha (1+cos \alpha )}{2sin \alpha (1-cos \alpha )} = \frac{1+cos \alpha }{1-cos \alpha } \\ cos \alpha = \frac{1}{5}=0,2; \frac{1+0,2}{1-0,2} = \frac{1,2}{0,8} = \frac{12}{8} = \frac{3}{2}=1,5 [/latex]