Pretty sure the first one is C
Answer:
can you please be more specific? Maybe add more info.
Step-by-step explanation:
or , where is an integer.
There are three such angles between and : , , and .
By the double angle identity of sines:
.
Rewrite the original equation with this identity:
Note, that and share the common factor . On the other hand, and share the common factor . Combine these terms pairwise using the two common factors:
Note the new common factor . Therefore:
This equation holds as long as either or is zero. Let be an integer. Accordingly:
Any that fits into at least one of these patterns will satisfy the equation. These pattern can be further combined: