Solve the equation for a in [0, 2pie]
A.) cosē(a) + 3cos(a) = -cos(a)
B.)sin(2a) = cos(a)
Add to both sides to get and now . Therefore, or . The second condition, is impossible because . The first condition is . That happens when
Using the double angle identity we get . Now factor, . Thus, we get two possibilities, or . The first condition, , gives . The second condition, is equivalent to saying , thus, .B.)sin(2a) = cos(a)