我们希望在整个 <span class="MathJax" id="MathJax-Element-2-Frame" tabindex="0" data-mathml="1≤x≤5，1≤y≤5" role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-; min-height: 0px; border: 0px; position: relative;">，1≤x≤5，1≤y≤5的正方形区域内得到<span class="MathJax" id="MathJax-Element-3-Frame" tabindex="0" data-mathml="z=sin(y)1+x2" role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-; min-height: 0px; border: 0px; position: relative;">z=sin(y)1+x2。试建立一个数据框 df ，步长为0.1，三列分别为 <span class="MathJax" id="MathJax-Element-4-Frame" tabindex="0" data-mathml="x,y,z" role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-; min-height: 0px; border: 0px; position: relative;">x,y,z 的值。

试用 geom_tile 和 geom_contour 分别画出 <span class="MathJax" id="MathJax-Element-5-Frame" tabindex="0" data-mathml="z" role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-; min-height: 0px; border: 0px; position: relative;">z 的图像，并描述 <span class="MathJax" id="MathJax-Element-6-Frame" tabindex="0" data-mathml="z" role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-; min-height: 0px; border: 0px; position: relative;">z 在 <span class="MathJax" id="MathJax-Element-7-Frame" tabindex="0" data-mathml="x,y" role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-; min-height: 0px; border: 0px; position: relative;">x,y 平面的单调性。