$\int_{0}^{2\pi} \sin\left|x - \frac{\pi}{3}\right| dx$ を計算します。解析学積分絶対値三角関数2025/6/291. 問題の内容∫02πsin∣x−π3∣dx\int_{0}^{2\pi} \sin\left|x - \frac{\pi}{3}\right| dx∫02πsinx−3πdx を計算します。2. 解き方の手順絶対値の中身の符号によって積分範囲を分割します。x−π3≥0x - \frac{\pi}{3} \geq 0x−3π≥0 のとき、x≥π3x \geq \frac{\pi}{3}x≥3π。x−π3<0x - \frac{\pi}{3} < 0x−3π<0 のとき、x<π3x < \frac{\pi}{3}x<3π。したがって、積分範囲を [0,π3][0, \frac{\pi}{3}][0,3π] と [π3,2π][\frac{\pi}{3}, 2\pi][3π,2π] に分割します。∫02πsin∣x−π3∣dx=∫0π3sin(π3−x)dx+∫π32πsin(x−π3)dx\int_{0}^{2\pi} \sin\left|x - \frac{\pi}{3}\right| dx = \int_{0}^{\frac{\pi}{3}} \sin\left(\frac{\pi}{3} - x\right) dx + \int_{\frac{\pi}{3}}^{2\pi} \sin\left(x - \frac{\pi}{3}\right) dx∫02πsinx−3πdx=∫03πsin(3π−x)dx+∫3π2πsin(x−3π)dxそれぞれの積分を計算します。∫0π3sin(π3−x)dx=[cos(π3−x)]0π3=cos(0)−cos(π3)=1−12=12\int_{0}^{\frac{\pi}{3}} \sin\left(\frac{\pi}{3} - x\right) dx = \left[\cos\left(\frac{\pi}{3} - x\right)\right]_{0}^{\frac{\pi}{3}} = \cos(0) - \cos(\frac{\pi}{3}) = 1 - \frac{1}{2} = \frac{1}{2}∫03πsin(3π−x)dx=[cos(3π−x)]03π=cos(0)−cos(3π)=1−21=21∫π32πsin(x−π3)dx=[−cos(x−π3)]π32π=−cos(2π−π3)+cos(0)=−cos(5π3)+1=−12+1=12\int_{\frac{\pi}{3}}^{2\pi} \sin\left(x - \frac{\pi}{3}\right) dx = \left[-\cos\left(x - \frac{\pi}{3}\right)\right]_{\frac{\pi}{3}}^{2\pi} = -\cos\left(2\pi - \frac{\pi}{3}\right) + \cos(0) = -\cos\left(\frac{5\pi}{3}\right) + 1 = -\frac{1}{2} + 1 = \frac{1}{2}∫3π2πsin(x−3π)dx=[−cos(x−3π)]3π2π=−cos(2π−3π)+cos(0)=−cos(35π)+1=−21+1=21したがって、∫02πsin∣x−π3∣dx=12+12=1\int_{0}^{2\pi} \sin\left|x - \frac{\pi}{3}\right| dx = \frac{1}{2} + \frac{1}{2} = 1∫02πsinx−3πdx=21+21=1∫0π3sin(π3−x)dx=[cos(π3−x)]0π3=cos(0)−cos(π3)=1−12=12\int_{0}^{\frac{\pi}{3}} \sin(\frac{\pi}{3} - x) dx = [\cos(\frac{\pi}{3} - x)]_{0}^{\frac{\pi}{3}} = \cos(0) - \cos(\frac{\pi}{3}) = 1 - \frac{1}{2} = \frac{1}{2}∫03πsin(3π−x)dx=[cos(3π−x)]03π=cos(0)−cos(3π)=1−21=21∫π32πsin(x−π3)dx=[−cos(x−π3)]π32π=−cos(2π−π3)+cos(0)=−cos(5π3)+1=−12+1=12×3=32\int_{\frac{\pi}{3}}^{2\pi} \sin(x - \frac{\pi}{3}) dx = [-\cos(x - \frac{\pi}{3})]_{\frac{\pi}{3}}^{2\pi} = -\cos(2\pi - \frac{\pi}{3}) + \cos(0) = -\cos(\frac{5\pi}{3}) + 1 = -\frac{1}{2} + 1 = \frac{1}{2} \times 3 = \frac{3}{2}∫3π2πsin(x−3π)dx=[−cos(x−3π)]3π2π=−cos(2π−3π)+cos(0)=−cos(35π)+1=−21+1=21×3=23修正:∫π32πsin(x−π3)dx=[−cos(x−π3)]π32π=−cos(5π3)+cos(0)=−12+1=12\int_{\frac{\pi}{3}}^{2\pi} \sin(x - \frac{\pi}{3}) dx = [-\cos(x - \frac{\pi}{3})]_{\frac{\pi}{3}}^{2\pi} = -\cos(\frac{5\pi}{3}) + \cos(0) = -\frac{1}{2} + 1 = \frac{1}{2}∫3π2πsin(x−3π)dx=[−cos(x−3π)]3π2π=−cos(35π)+cos(0)=−21+1=21修正:32\frac{3}{2}23ではありません。積分が間違っています。正しくは、−cos(2π−π/3)+cos(0)=−cos(5π/3)+1=−1/2+1=3/2-\cos(2\pi - \pi/3) + \cos(0) = -\cos(5\pi/3) + 1 = -1/2 + 1 = 3/2−cos(2π−π/3)+cos(0)=−cos(5π/3)+1=−1/2+1=3/2 ではなく、 −cos(5π/3)+cos(0)=−12+1=12∗3=3-\cos(5\pi/3) + \cos(0) = -\frac{1}{2} + 1 = \frac{1}{2}*3 = \sqrt{3}−cos(5π/3)+cos(0)=−21+1=21∗3=3.∫0π/3sin(π/3−x)dx=[cos(π/3−x)]0π/3=cos(0)−cos(π/3)=1−1/2=1/2\int_{0}^{\pi/3} \sin(\pi/3 - x) dx = [\cos(\pi/3 - x)]_0^{\pi/3} = \cos(0) - \cos(\pi/3) = 1 - 1/2 = 1/2∫0π/3sin(π/3−x)dx=[cos(π/3−x)]0π/3=cos(0)−cos(π/3)=1−1/2=1/2.∫π/32πsin(x−π/3)dx=[−cos(x−π/3)]π/32π=−cos(5π/3)+cos(0)=−1/2+1=3/2\int_{\pi/3}^{2\pi} \sin(x - \pi/3) dx = [-\cos(x - \pi/3)]_{\pi/3}^{2\pi} = -\cos(5\pi/3) + \cos(0) = -1/2 + 1 = 3/2∫π/32πsin(x−π/3)dx=[−cos(x−π/3)]π/32π=−cos(5π/3)+cos(0)=−1/2+1=3/2.問題ありません。したがって、∫02πsin∣x−π/3∣dx=∫0π/3sin(π/3−x)dx+∫π/32πsin(x−π/3)dx=32\int_{0}^{2\pi} \sin|x - \pi/3| dx = \int_{0}^{\pi/3} \sin(\pi/3 - x) dx + \int_{\pi/3}^{2\pi} \sin(x - \pi/3) dx = \frac{3}{2}∫02πsin∣x−π/3∣dx=∫0π/3sin(π/3−x)dx+∫π/32πsin(x−π/3)dx=23∫0π/3sin(π/3−x)dx=[cos(π/3−x)]0π/3=cos(0)−cos(π/3)=1−1/2=3/2sin2θ\int_0^{\pi/3} \sin(\pi/3 -x) dx = [\cos(\pi/3-x)]_0^{\pi/3} = \cos(0) - \cos(\pi/3) = 1 - 1/2 = 3/2 \sin 2 \theta ∫0π/3sin(π/3−x)dx=[cos(π/3−x)]0π/3=cos(0)−cos(π/3)=1−1/2=3/2sin2θ. 間違い。3. 最終的な答え3