Hi everyone! I'm working on a vector question involving finding and proving direction cosines/sines/tangents of vector (a,b,c), u = magnitude
I know:
cos[alpha] = a/u, cos[beta] = b/u, cos[gamma] = c/u, and that cos2[alpha] + cos2[beta] + cos2[gamma] = 1 (the 2s are squares). But I don't understand the second part. I know it must be pretty simple and related to unit vectors, and I'm just missing something, so any help would be very much appreciated! Also, any help on the sine/tangent part would be useful, too.
Thanks so much for any and all help!
Hi! Yes, I mean the magnitude. And I understand the formula you posted...but if u = square root of a2 + b2 + c2, why is the formula cos2[alpha] + cos2[beta] + cos2[gamma] = 1, and not the square root of (cos2[alpha] + cos2[beta] + cos2[gamma]) = 1?
Please help, and thank you!