Joe Biden took charge as the 46th president of the United States on Wednesday with an upbeat call to heal a nation torn by deep schisms as he immediately erased some of Donald Trump's most divisive policies.In his inaugural address, Biden appealed to supporters of Trump, who shattered political norms by ruthlessly belittling rivals, denouncing entire ethnic groups and trying to cast doubt on basic facts."I will be a president for all Americans," the veteran Democrat said.