Determine the solutions to the equation 2sinx − cos2x = sin2x for 0 ≤ x ≤ 2π .
How do I start this question?
8 answers
do you mean sin(2x) or sin^2 x ???
Sorry, I meant 2sinx - cos^2x = sin^2x for 0 ≤ x ≤ 2π
2sinx - cos^2x = sin^2x
Do I change the left side to
2sinxcosx - cos^2x = sin^2x
2sinx - cos^2x = sin^2x
Do I change the left side to
2sinxcosx - cos^2x = sin^2x
2 sin x = sin^2 x + cos^2 x = 1
sin^2 x + cos^2 x = 1 VERY IMPORTANT trig identity
sin x = 1/2
x = 30 degrees or 150 degrees
x = 30 degrees or 150 degrees
Thank you~
May I know how you got 150 degrees? I am so confused when finding the reference angles, whether to subtract or add the degrees.
May I know how you got 150 degrees? I am so confused when finding the reference angles, whether to subtract or add the degrees.
well I just looked for 30 degrees above and below the x and - x axis and picked the one where sin was positive. That is in quadrants 1 and 2. 180-30 = 150
Thank you!