Question

I believe I've found an alternate solution to problem set 3 #2b from part b.Could someone let me know what they think? I'll attach an image of the problem and the solution.

Answer 1

I meant 2a. Here are the attachments. I posted several formats of the solution.
Thanks in advance.

Answer 2

its incorrect...

Answer 3

u and v are given, constant unit vectors.
t is a variable.
thus cos(t) is a variable

look at
\[\cos(t)=\frac{|u|}{|u+v|}\]

the left side is a variable, and the right side is a constant.

Answer 4

the problem here lies in your understanding of 't'
t is not an angle measured with respect to anything.

rather, its representative of the components of the position vector varying sinusoidally

Answer 5

next time please provide link to the question as well :)

Answer 6

Maybe with some work we can "patch up" your idea. (For starters, "your" u would have to be \( (\cos t)\ \hat{u} \) where \(\hat{u}\) is "their" unit length u. Ditto for v)

But it would make sense to first do the problem using the definition of magnitude squared of a vector, using the dot product:
\[ | \vec{v}|^2 = \vec{v}\cdot \vec{v} \]

Answer 7

Baru, the screenshot of the question is the first attachment ( I mentioned I would attach it in the original question). Thanks to both of you for your help.