46:15 Holy shit! He gave a teaser to abstract algebra right there! I just finished abstract algebra and was just watching these lectures because... I don't need a reason, and I just noticed that now! Prof Strang is amazing. I am glad I can watch these lectures from anywhere and at anytime I want :)####[['abstract algebra', 'Course_General_Feedback', 'POS'], ['NULL', 'Instructor', 'POS'], ['Prof Strang', 'Instructor', 'POS'], ['lectures', 'Course_General_Feedback', 'POS']]