In defense of the seniors... It generally takes people several semesters of Linear Algebra to become competent with "matrix stuff." It's unrealistic to expect every senior dev to also be an expert teacher -- never mind expecting them to know what the latest and best learning resources are (for a subject they may have learned, themselves, before the Web was invented).
Sometimes the right and fair substitute for "nothing I can do will help you" is "get yourself a proper education on this subject, somehow, and then we can talk about the code."
Sometimes the right and fair substitute for "nothing I can do will help you" is "get yourself a proper education on this subject, somehow, and then we can talk about the code."