Question Number 164483 by mathlove last updated on 18/Jan/22
$$\frac{{cos}\mathrm{25}−{sin}\mathrm{65}}{{sin}\mathrm{20}+{sin}\mathrm{10}}=? \\ $$
Commented by som(math1967) last updated on 18/Jan/22
$$\mathrm{0} \\ $$
Answered by Rasheed.Sindhi last updated on 18/Jan/22
$$\frac{{cos}\mathrm{25}−{sin}\mathrm{65}}{{sin}\mathrm{20}+{sin}\mathrm{10}} \\ $$$$=\frac{{sin}\left(\mathrm{90}−\mathrm{25}\right)−{sin}\mathrm{65}}{{sin}\mathrm{20}+{sin}\mathrm{10}} \\ $$$$=\frac{{sin}\mathrm{65}−{sin}\mathrm{65}}{{sin}\mathrm{20}+{sin}\mathrm{10}} \\ $$$$=\frac{\mathrm{0}}{{sin}\mathrm{20}+{sin}\mathrm{10}}=\mathrm{0}\: \\ $$$$ \\ $$