I cannot change the root password in mysql from the error when using the command

Question

The moment I give the command

update user set authentication_string=password('root') where user = 'root';

to exchange the root password the following error appears in mysql:

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that Corresponds to your Mysql server version for the right syntax to use near '('root') Where user = 'root'' at line 1

The sequence of commands I gave before I arrived at this error was:

sudo service mysql stop

sudo mysqld_safe --skip-grant-tables

sudo service mysql start

sudo mysql -u root

use mysql;

show tables;

describe user;

update user set authentication_string=password('root') where user = 'root';