函數(shù)y=Asin(ωx+φ)的圖象課件

1、第4課時函數(shù)yAsin(x)的圖象 第4課時函數(shù)yAsin(x)的圖象 函數(shù)y=Asin(x+)的圖象課件1yAsin(x)的有關(guān)概念 yAsin(x)(A0，0)，x0，)表示一個振動量時振幅周期頻率相位初相Tf Ax1yAsin(x)的有關(guān)概念 yAsin(x2.用五點(diǎn)法畫yAsin(x)一個周期內(nèi)的簡圖用五點(diǎn)法畫yAsin(x)一個周期內(nèi)的簡圖時，要找五個特征點(diǎn)如下表所示：xxyAsin(x)0A0A0022.用五點(diǎn)法畫yAsin(x)一個周期內(nèi)的簡圖xx【思考探究】找五個點(diǎn)時，在上表的三行中，應(yīng)首先確定哪一行的數(shù)據(jù)？函數(shù)y=Asin(x+)的圖象課件答案：C 答案：C 答案：B 答案：

2、B 答案：B 答案：B 函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件列表，并描點(diǎn)畫出圖象：列表，并描點(diǎn)畫出圖象：函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件【注意】當(dāng)不能確定周期T時，往往要根據(jù)圖象與y軸的交點(diǎn)，先求.【注意】當(dāng)不能確定周期T時，

3、往往要根據(jù)圖象與y軸的交點(diǎn)，先函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件形如yasin xbcos x，yasin2xbsin xcos xccos2x等函數(shù)可化為yAsin(x)k的形式，進(jìn)而可解決三角函數(shù)的圖象和性質(zhì)等問題形如yasin xbcos x，yasin2xbsi函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)

4、的圖象課件1五點(diǎn)法作函數(shù)圖象及函數(shù)圖象變換問題(1)當(dāng)明確了函數(shù)圖象基本特征后，“描點(diǎn)法”是作函數(shù)圖象的快捷方式運(yùn)用“五點(diǎn)法”作正、余弦型函數(shù)圖象時，應(yīng)取好五個特殊點(diǎn)，并注意曲線的凹凸方向(2)在進(jìn)行三角函數(shù)圖象變換時，提倡“先平移，后伸縮”，但“先伸縮，后平移”也經(jīng)常出現(xiàn)在題目中，所以也必須熟練掌握，無論是哪種變形，切記每一個變換總是對字母x而言，即圖象變換要看“變量”起多大變化，而不是“角”變化多少1五點(diǎn)法作函數(shù)圖象及函數(shù)圖象變換問題函數(shù)y=Asin(x+)的圖象課件4注意復(fù)合形式的三角函數(shù)的單調(diào)區(qū)間的求法函數(shù)yAsin(x)(A0，0)的單調(diào)區(qū)間的確定，基本思想是把x看做一個整體在單調(diào)性應(yīng)用方面，比較大小是一類常見的題目，依據(jù)是同一區(qū)間內(nèi)函數(shù)的單調(diào)性函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件從近兩年的高考試題來看，函數(shù)yAsin(x)的圖象的平移和伸縮變換以及根據(jù)圖象確定A、問題是高考的熱點(diǎn)，題型既有選擇題、填空題，又有解答題，難度中低檔，主要考查識圖、用圖能力，同時考查了利用三角公式進(jìn)行三角恒等變換的能力函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件函數(shù)y=Asin(x+)的圖象課件答案：D 答