Using the summation identity will be: =sin([tex] \pi [/tex])+cos([tex] \pi [/tex])sin([tex] \frac{ \pi }{4} [/tex]) By following the trivial identity, you should get: =0*[tex] \frac{ \sqrt{2}}{2}+(-1) \frac{\sqrt 2} {2} [/tex]
Remove the parentheses on -1, then multiply =0*[tex] \frac{ \sqrt 2} {2}-1* \frac{ \sqrt 2} {2} [/tex]
You should get: [tex]- \frac{ \sqrt 2} {2} [/tex]
