2015 National Question 2 Single-choice Differentiating 2015_退役省自主命题 (2015·理) (2)下列函数中,既是偶函数又存在零点的是 A. $y=\cos x$B. $y=\sin x$C. $\mathrm{y}=\ln x$D. $y=x^{2}+1$ Answer keyA ☆ SaveCan't do it, show the explanation查看原卷 →