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Find all solutions from 0 to 2π

Find all solutions from 0 to 2π-example-1
User Rognon
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The solutions for the equation sin(θ + π/4) = 1/2 in the interval [0, 2π] are:

θ1 = 0.523 radians + 2πn, where n is any non-negative integer.

θ2 = 1.893 radians + 2πn, where n is any non-negative integer.

θ3 = 7.369 radians + 2πn, where n is any non-negative integer.

1. Solve for θ + π/4:

Take the arcsine (sin^-1) of both sides:

θ + π/4 = arcsin(1/2)

Arcsine has two solutions in the interval [0, 2π], because sine is periodic:

θ + π/4 = π/6 + 2πn or θ + π/4 = 5π/6 + 2πn

where n is any integer.

2. Solve for θ:

Subtract π/4 from both sides in each equation:

θ = π/6 + 2πn - π/4 or θ = 5π/6 + 2πn - π/4

Simplify:

θ = -π/12 + 2πn or θ = 7π/12 + 2πn

3. Find solutions in the interval [0, 2π]:

For the first solution, substitute n = 0, 1, 2, ... until θ is greater than or equal to 2π:

θ1(0) = -π/12 = 0.523 radians

θ1(1) = -π/12 + 2π = 5.999 radians

θ1(2) = -π/12 + 4π = 11.471 radians

The first solution that falls within the interval [0, 2π] is θ1(0) = 0.523 radians.

For the second solution, substitute n = 0, 1, 2, ... until θ is greater than or equal to 2π:

θ2(0) = 7π/12 = 1.893 radians

θ2(1) = 7π/12 + 2π = 7.369 radians

θ2(2) = 7π/12 + 4π = 12.845 radians

Both θ2(0) = 1.893 radians and θ2(1) = 7.369 radians fall within the interval [0, 2π].

User Gordon Dove
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