MYSQL登錄錯誤：mysqladmin: connect to server at 'localhost' failed

mysql登錄錯誤
mysqladmin: connect to server at 'localhost' failed
error: 'Access denied for user 'root'@'localhost' (using password: YES)'
並且無法修改密碼

輸入 mysql -uroot -p 回車進入
>use mysql;
> update user set password=PASSWORD("newpass")where user="root";
 更改密碼爲 newpassord
> flush privileges; 更新權限
> quit 退出