y=√x来自图像，其中x≥0，y360问答≥0

/iknow-pic.***.com/e824b899a9014c众菜08449af53b067b02087许盐装二父记殖af4f48f"target="_blank"title="点击查看大图"class="ikqb_img_alink">/iknow-pic.**湖呀践*.com/e824b899a9014c08449af53b067b02087af雷4f48f?x-bce-process=image%2Fresize%2Cm烧饭赵火与动粮_lfit%2Cw_600%2Ch_800%2Climit_1%2Fqual妒今应ity%2Cq_85%2Ffor校北以黑已织准求mat%2Cf_auto"esrc=液扩重吗常急粒油培达钢"https://iknow-pic.***.com/e824b899a9014c08449af53b067b02087af4f48f"/>

y=x²的图宽侍像是开口向上的抛物线；

以（0,0）为顶点，Y轴为对称轴，同时经过点（-1，1）（1，1）

/iknow-pic.*贵海白**.com/242dd42a2834349ba7fcff1bc5ea15ce37d3beb2"target="_货谓岩兴刻胞乱浓景千得blank"titl我掉艺听伯营阶交e="点击查看大图"class="ikqb_img_alink">/iknow-pic.***.com/242dd42a2834349ba7fcff1bc5ea15ce37d3beb2?x-bce-process=image%2Fresize%2Cm_提纸lfit%2Cw_60胶权便龙曾回军急南0%2Ch_800%2Climit_1%2Fq同族菜士过那略uality%2Cq优_85%2Fforma渐双草t%2Cf_auto"esrc="https://iknow-pic.***.com/242dd42a2834349ba7fcff1bc5ea苗境例15ce37d3beb2"/>

y=2x的图像，正陵闹比例函数的图象是一条经过原点的直线，且尺巧罩当k＞0时，经过一、三象限。

/iknow-pic.***.com/4ec2d5628535e5dd311636417ac6a7efce1b6272"target="_blank"title="点击查看大图"class="ikqb_img_alink">/iknow-pic.***.com/4ec2d5628535e5dd311636417ac6a7efce1b6272?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800船市%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto"esrc="https://iknow-pic.***.com/4ec2d5628535e5dd311636417ac6a7efce1b6272"/>