Respuesta :

evgeniylevi
Try this option (this is only one way):
1. rule: 
[tex]sin \alpha =cos( \frac{ \pi }{2} - \alpha)[/tex]
2. according to the rule
[tex]sin75=0.966=cos( \frac{ \pi}{2} -75)=cos15[/tex]

answer: cos15°.