Recent content by cupu

Hello, Thanks for the reply. My problem is just that when I think about reference angles, they make sense because of the periodic nature of trig functions; then I think that the periodicity is there because we use reference angles to compute the values of trig functions for angles between...

Hello, Preparing for a test, I've had to go through some very basic trigonometry and I've got to thinking why reference angles "work". I've gone through my study material and through another trigonometry book I have around the house and references angles are never proven, the theorem is just...

@micromass @spamiam Thanks for the replies, I've seen other proofs which I've been able to workout on paper and those make sense, I just got really hung up on this specific 'proof' because I couldn't make sense of the red part. @sahil_time @Fredrik Thank you! I though that the 'proof'...

Hello, Looking through a book on calculus I found the following explanation for the chain rule and I have one unclear thing that I'd like to ask for help on. The canonical example is used, y is a function of u: y = u^{n} and u is a function of x (let's say) u = 3x - 2 therefore by composition...

That makes sense, thank you very much for the response Mark44.

Hello, In a book I'm reading about linear algebra it's mentioned that in order for the homogeneous system Ax = 0 to have a solution (other than the trivial solution) the coefficient Matrix must be singular. The thing is, I can't remember (the wikipedia page on homogeneous systems didn't turn up...