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三角函数的图象是函数图象的重要组成部分,在高考试卷中占重要位置,且囊括了常见函数所共有的性质.除此之外,三角函数的周期性和对称性,显示出独特之处.三角函数的图象在解决问题时有两大类:根据图象寻求表达式;给出表达式研究函数的性质有时也和其他知识点交汇.一图象的变换例1(2005年高考天津卷)要得到函数)y=2~(1/2)cosx的图象,只需将函数y=2~(1/2)sin(2x+π/4)的图象上所有的点的()(A)横坐标缩短到原来的1/2倍(纵坐标不变),再向左平行移动π/8个单位长度.
The image of the trigonometric function is an important part of the function image, which occupies an important position in the examination paper, and includes the properties common to common functions. In addition, the periodicity and symmetry of the trigonometric function show a unique At the same time, the image of trigonometric functions has two major categories when it comes to solving problems: it seeks expressions based on images; the properties of the given expressions study functions sometimes converge with other points of knowledge. Example 1 of an image transformation (2005 college entrance examination Tianjin Volume) To get the image of function y=2~(1/2)cosx, just put all the points on the image of the function y=2~(1/2)sin(2x+π/4) () (A) The abscissa is shortened to 1/2 times its original value (the ordinate does not change), and then it moves parallel to the left by π/8 units of length.