Answer :
I believe you're referring to "objectivity", not "objective" here. The resume should include only factual statements about your past employment, training, and education.
A business letter should not be included in your resumé. You can even send it with your resumé, but it shouldn't be included in it. The informations regarding your education, contact information, your objective, and employment history are a MUST in a resumé and should always be included.