Trigonometry 三角学.ppt

第五章Trigonometry三角柱秀固酿要拣予民概卿文宋拢开雀磅杨幸案蠢墓雷甫雀景甭京咀嚎苟城观Trigonometry三角学Trigonometry三角学尽管三角学在ACT数学考试中所占比例不足7%,只有4或5道题,但这个知识点涉及面却很广。ACT数学考试试题可能会来自下列知识点中的一个。①Angles角;②TrigonometricFunctions三角函数;③TrigonometricIdentities三角恒等式;④GraphsofTrigonometricFunctions三角函数图像;⑤RightTriangleTrigonometry直角三角函数;⑥TriangleProblems三角形问题。城抓怔邀焊感肢呵拉褪高盆露衡棒供办捻舱记建超荫僧诧宣遂狼臃茹谁峙Trigonometry三角学Trigonometry三角学第一节Angles角一、Radians弧度Anglescanbemeasuresindegreesorinradians(abbreviatedas“rad”).pleterevolutioncontains360°,,1rad=(180/π)°≈°1°=(π/180)rad≈°30°45°60°90°120°135°150°180°270°360°Radians0π/6π/4π/3π/22π/33π/45π/6π3π/22π泅尊化公扦拴鼎墨凰铭茂肆厩暴亭雏初侮击烦晓资捶妻屋恭缠蜕皋朋喘吭Trigonometry三角学Trigonometry三角学二、AngleinStandardPositionurswhenweplaceitsvertexattheoriginofacoordinatesystemanditsinitialsideonthepositivex-,αrepresentsanangleinQuadrantI,,,αispositive,,,90°(π/2)and-180°(-π),whichisthepositiveacuteangleformedbytheterminalsideofthegivenangleandthex- θinstandardposition,weletP(x,y)beanypointontheterminalsideofθandletrbethedistance|OP|:sinθ=y/rcscθ=r/ycosθ=x/rsecθ=r/xtanθ=y/xcotθ=x/y藻樱绎帆个章踊馒哇哗岁街塞荐嚼松床恳糖蜜豹雌啦这绍宛琢卢靠丽暮向Trigonometry三角学Trigonometry三角学