Question

express the tan(22.5) using the cos(45)

Answer 1

\[22.5=\frac{45}{2} \\ \tan(\frac{45}{2}) =?..\text{ use half angle identity }\]

Answer 2

you may also consider expressing sin(45) as cos(45)
you can do this since sin(45)=cos(45)
I'm only saying this since they want you to express your answer in terms of cos(45)

Answer 3

I got -1-sqrt of 2 all over 1 so it seems right lol