I'll write "x" instead theta.
sin x + 1 = cos(2x)
formula: cos(2x) = 1 - 2sin²x
sin x + 1 = 1 - 2sin²x
2sin²x + sin x = 0
sin x (2sin x + 1) = 0
sin x = 0 or sin x = -1/2
x1 = πk and x2 = -π/6 + 2πk and
x3 = 5π/6 + 2πk
for domain 0≤x<2π :
x1 = 0 (for k=0 in x1)
x2 = π (for k=1 in x1
x3 = 11π/6 (for k=1 in x2)
x4 = 5π/6 (for k=0 in x3).
k is an integral.
Im confused can you please clarify?
Y = 10 degrees
work:
6y + 3 + 4y - 13 = 90
6y + 4y = 90 + 13 - 3
10y = 100
y = 10
$6.67 is 6.6666 rounded to the nearest cent.
