函數(shù)y=(25x-19cosx)(35x+68sinx)的圖像示意圖主要內(nèi)容：本文根據(jù)三角正弦函數(shù)和余弦函數(shù)的周期性，并通過描點法，詳細介紹函數(shù)y=(25x-19cosx)(35x+68sinx)的圖像示意圖畫法步驟。函數(shù)的定義域：根據(jù)本題涉及的函數(shù)及其特征，為一次函數(shù)和三角函數(shù)和差的乘積，可知自變量x可以取任意實數(shù)，所以：函數(shù)y=(25x-19cosx)(35x+68sinx)的定義域為：(-∞，+∞)。函數(shù)描點原則：由于三角函數(shù)具有周期性，本題用描點法畫函數(shù)y=(25x-19cosx)(35x+68sinx)的圖像。考慮周期性，本例需畫出在區(qū)間[-4π，4π]上的圖像示意圖，故取點原則為間隔1/4個周期進行取點。函數(shù)特征點圖表：x-4π-3.75π-3.5π-3.25π-3π-2.75π25x-19cosx-333.2-308.0-274.9-241.8-216.6-202.535x+68sinx-439.8-364.3-316.8-309.3-329.9-350.5y14654111220487088747897145670976x-2.5π-2.25π-2π-1.75π-1.5π-1.25π25x-19cosx-196.3-190.1-176.1-150.9-150.9-84.735x+68sinx-342.9-295.5-219.9-144.3-96.9-89.4y67311561753872421775146227572x-π-0.75π-0.5π-0.25π00.25π25x-19cosx-59.5-45.5-39.3-33.1-196.235x+68sinx-110.0-130.6-123.0-75.6075.6y65455942483425020469x0.5π0.75ππ1.25π1.5π1.75π25x-19cosx39.372.397.5111.6117.8124.035x+68sinx123.0130.6110.089.496.9144.3y483494421072599771141517893x2π2.25π2.5π2.75π3π3.25π25x-19cosx138.1163.3196.3229.4254.6268.735x+68sinx219.9295.5342.9350.5329.9309.3y303684825567311804058399383109x3.53.75π4π25x-19cosx274.9281.1295.235x+68sinx316.8364.3439.8y87088102405129829函數(shù)圖像示意圖：y=(25x-19cosx)(35x+68sinx)y (-4π,146541)(4π,129829)(3π,83993)(3.5π,87088)(-3.25π,74789)(-2.5π,67311)(-3π,71456)(2π,30368)(-π,6545)x