This is actually not a full problem, just a part of one I'm having trouble with:(adsbygoogle = window.adsbygoogle || []).push({});

1. The problem statement, all variables and given/known data

If I have a acceleration vector, say [ b[itex]k^{2}[/itex][itex]e^{kt}[/itex] - b[itex]c^{2}[/itex][itex]e^{kt}[/itex] ][itex]e_{r}[/itex] + [ 2bkc[itex]e^{kt}[/itex] ] [itex]e_{θ}[/itex]. How can I find its magnitude?

2. Relevant equations

Mag vector |a| = (a^2)^(1/2)

3. The attempt at a solution

As I square [itex]_{e}r[/itex], the cross term is still negative under the radical, and doesn't subtract cleanly:

[ [itex]b^{2}k^{4}e^{kt}[/itex] + [itex]b^{2}c^{4}e^{kt}[/itex] - 2[itex]b^{2}k^{2}c^{2}e^{kt}[/itex] ][itex]^{1/2}[/itex]

I'm either doing some wrong algebra or missing something obvious I think?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Magnitude of vector, negative in part.

**Physics Forums | Science Articles, Homework Help, Discussion**