Question

Докажите 4cos25-3sin65/sin115=1

Answer 1

$\frac{4cos25-3sin65}{sin115}=\frac{4cos(\frac{\pi }{2}-65)-3sin65 }{sin(\pi-65)}= \frac{4sin65-3sin65}{sin65}=\frac{sin65}{sin65}=1$