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Multiple Choice
Identify the intervals on which the function is increasing or decreasing. f(x)=sin2x on [0,π]
A
Increasing on [0,π]
B
Decreasing on [0,π]
C
Increasing on [0,2π), Decreasing on (2π,π]
D
Increasing on (2π,π], Decreasing on [0,2π)
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검증된 단계별 안내
1
First, understand that to determine where the function f(x) = sin^2(x) is increasing or decreasing, we need to find its derivative, f'(x). This will help us identify the critical points and intervals of increase or decrease.
Calculate the derivative of f(x) = sin^2(x). Use the chain rule: if f(x) = (sin(x))^2, then f'(x) = 2 * sin(x) * cos(x). This simplifies to f'(x) = sin(2x) using the double angle identity.
Set the derivative f'(x) = sin(2x) equal to zero to find the critical points. Solve sin(2x) = 0 for x in the interval [0, π]. The solutions are x = 0, π/2, and π.
Analyze the sign of f'(x) = sin(2x) in the intervals determined by the critical points: [0, π/2), (π/2, π]. If f'(x) > 0, the function is increasing; if f'(x) < 0, the function is decreasing.
Conclude the intervals: f(x) is increasing on [0, π/2) because sin(2x) > 0, and decreasing on (π/2, π] because sin(2x) < 0.