Apologise if this question isn't relevant to this forum, I tried my best to look for similar questions but couldn't find one.
I am a computer science major enrolled in a not-so-renowned university in India.
I am in my pre-final year and have taken four math courses. While I did well in the first two (got an O grade i.e the highest grade possible), due to some personal problems, I got a D and a C in the next two courses. Unfortunately, my university does not have a provision to retake the courses.
My eventual plan is to apply for grad school in fields such as machine learning where they require a strong math background.
My question is: how can I show that I know the required math for the courses beyond my uni courses?
One way I thought was of doing MOOCs on the subjects and uploading my solutions to them somewhere? But the general consensus which I found here was that MOOCs don't hold much value when it comes to showing proficiency in a subject.
What are some other ways in which I can demonstrate my proficiency in the subject?
EDIT: The courses where I fared poorly included the following topics (since it's an engineering course, we don't have specific courses like Linear Algebra or Statistics - we instead learn an overview of mixture of a few math subjects each semester) - Fourier Analysis, Laplace Transform, Vector Algebra, Complex Variable and Mapping, Z-transform, Complex Integration, Matrices, Probability, Sampling Theory and Mathematical Programming.)