Find all values of x such that sin(2x) = sin(x) and 0 ≤ x ≤ 2π
Solution:
Given, sin(2x) = sin(x), 0 ≤ x ≤ 2π -----(1)
Using trigonometry formula,
sin(2x) = 2 sinx cosx
Substituting the above formula in equation 1, we get
2 sinx cosx = sinx
2 sinx cosx - sinx = 0
Taking out common term,
⇒ sin x (2 cos x - 1) = 0
Now, sin x = 0
⇒ x = sin-1(0)
⇒ x = 0, π, 2π
Now, 2 cos x - 1 = 0
⇒ 2 cos x = 1
⇒ cos x = 1/2
⇒ x = cos-1(1/2)
x = π/3, 5π/3.
Therefore, the solutions are x = 0, π, 2π, π/3, 5π/3.
Find all values of x such that sin(2x) = sin(x) and 0 ≤ x ≤ 2π
Summary:
All values of x such that sin(2x) = sin(x) and 0 ≤ x ≤ 2π are x = 0, π, 2π, π/3, 5π/3.
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