1) $$\frac{tga + tg\beta}{ctga + ctg\beta} = \frac{tga + tg\beta}{\frac{1}{tga} + \frac{1}{tg\beta}} = \frac{tga + tg\beta}{\frac{tg\beta + tga}{tga \cdot tg\beta}} = \frac{(tga + tg\beta) \cdot tga \cdot tg\beta}{tga + tg\beta} = tga \cdot tg\beta$$