描点法画形如三角余弦函数y=x+cosax+b图像示意图过程C4

描点法画函数y=238x+cos(51x+99)的性质及其图像主要内容：本文根据余弦等函数的有关性质，介绍通过描点法画出三角函数y=238x+cos(51x+99)在区间[-EQ\F(4π+99,51),EQ\F(4π-99,51)]区间上图像示意图的主要过程与步骤。※.函数的定义域根据函数的特征，函数是一次函数y₁=238x和余弦函数y₂=cos(51x+99)的和函数，且二者的定义域为全体实数，所以其和函数的定义域也为全体实数，即为:(-∞，+∞)。※.函数描点思路由于函数y=238x+cos(51x+99)含有三角余弦函数，三角函数具有周期性值，故描点以三角函数为中心函数，分别取三角函数值为0，±1以及45°角时的取值为本例函数的特征点。※.函数的部分点图本处以区间[-EQ\F(4π+99,51),EQ\F(4π-99,51)]为例，描点列为：x-2.188-2.172-2.157-2.141-2.12651x+99-4π-15π/4-7π/2-13π/4-3πcos(51x+99)10.710-0.71-1238x-520.74-516.94-513.37-509.56-505.99y-519.74-516.23-513.37-510.27-506.99x-2.111-2.095-2.080-2.064-2.04951x+99-11π/4-5π/2-9π/4-2π-7π/4cos(51x+99)-0.7100.7110.71238x-502.42-498.61-495.04-491.23-487.66y-503.1-498.6-494.3-490.2-487.0x-2.034-2.018-2.003-1.987-1.97251x+99-3π/2-5π/4-π-3π/4-π/2cos(51x+99)0-0.71-1-0.710238x-484.09-480.28-476.71-472.91-469.34y-484.1-481.0-477.7-473.6-469.3x-1.957-1.941-1.926-1.910-1.895-1.88051x+99-π/40π/4π/23π/4πcos(51x+99)0.7110.7100.71-1238x-465.77-461.96-458.39-454.58-451.01-447.44y-465.1-461.0-457.7-454.6-451.7-448.4x-1.864-1.849-1.833-1.818-1.803-1.78751x+995π/43π/27π/42π9π/45π/2cos(51x+99)-0.7100.7110.710238x-443.63-440.06-436.25-432.68-429.11-425.31y-444.3-440.1-435.5-431.7-428.4-425.3x-1.772-1.756-1.741-1.726-1.710-1.69551x+9911/4π3π13π/47π/215π/44πcos(51x+99)-0.71-1-0.7100.711238x-421.74-417.93-414.36-410.79-406.98-403.41y-422.4-418.9-415.1-410.8-406.3-402.4※.函数的示意图y=238x+cos(51x+99) y (-1.695,-402.4)(-1.941,-461.0) x