関連ワード:  sine function key features    sine function key points    sinusoidal function key points    sine wave key points    a sine function has the following key features    a sine function has the following key features period 4    a sine function has the following key features period 4pi    a sine function has the following key features frequency 1 8pi    a sine function has the following key features period 4 amplitude 3    a sine function has the following key features frequency 1 4pi