Question

Use the unit circle to find the value of tan 315°.

Answer 1

let's recall, the x,y pairs are just the cosine,sine pairs.

`\stackrel{ \cos(315^o) ~~ \sin(315^o) }{\left( \cfrac{√(2)}{2}~~,~-\cfrac{√(2)}{2} \right)}\hspace{4.5em}\tan(315^o)\implies \cfrac{\sin(315^o)}{\cos(315^o)} \implies \cfrac{ ~~ -\cfrac{√(2)}{2} ~~ }{\cfrac{√(2)}{2}}\implies \text{\LARGE -1}`