Answer:
A. {60°, 120°, 420°}
B. θ = 15π/4; sec(θ) = √2
Step-by-step explanation:
A.
The sine function is periodic with period 360°, and it is symmetrical about the line θ = 90°. The reference angle for the given value of sin(θ) is ...
θ = arcsin(√3/2) = 60°
The next larger angle with the same sine is (2×90°) -60° = 120°. Any multiple of 360° added to either one of these angles will give an angle with the same sine. A possible set of 3 angles is ...
{60°, 120°, 420°}
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B.
One degree is π/180 radians, so the given angle in radians is ...
θ = 675° = 675(π/180) radians = 15π/4 radians
This angle has the same trig function values as 7π4, a 4th-quadrant angle with a reference angle of π/4, or 45° The secant of that angle is
sec(45°) = √2
The 4th-quadrant angle has the same sign, so ...
sec(675°) = sec(15π/4) = √2
