The answer will be Negative
Write sin([tex] \frac{5 \pi }{4} [/tex]) as sin([tex] \pi [/tex]+[tex] \frac{ \pi } {4} [/tex])
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]
