Question

3sin(2a-π/4)+2cos(3a-π) если a=π/4

Answer 1

$a=frac{pi}{4}\\3sin(2a-frac{pi}{4})+2cos(3a-pi )=3sin(frac{pi }{2}-frac{pi}{4})+2cos(frac{3pi }{4}-pi )=\\=3sinfrac{pi }{4}+2cos(-frac{pi}{4})=3cdot frac{sqrt2}{2}+2cdot frac{sqrt2}{2}=frac{5sqrt2}{2}$