2015 Anhui Question 4 Single-choice Differentiating 2015_省自主命题(安徽) (4)下列函数中,既是偶函数又存在零点的是() A. $y { = } l n x$B. $y = x ^ { 2 } + 1$C. $y=sinx$D. $y { = } c o s x$ Answer keyD ☆ SaveCan't do it, show the explanation查看原卷 →