Question

Simplify the following expression.

Answer 1

\[\sqrt{(7xcosx)^2+(-7xsinx+14cosx)^2}\]

Answer 2

the farthest i got to was\[\sqrt{49x^2-196sinxcosx+196\cos^2x}\]

Answer 3

We want the radical to go away if possible or get the least amount of terms under the radical at least.

Answer 4

Any idea @Preetha ?

Answer 5

if you are lucky it is a prefect square

Answer 6

doesn't look like one though, maybe some other trick

Answer 7

I factored out a 49 and pulled it out of the radical. I was thinking maybe a trig identity for cos^2x not sure though.

Answer 8

was that thing really the initial problem?

Answer 9

Well if you want the initial problem I'll go ahead and give it to you.

Answer 10

the 49 comes out for sure
not sure what else you can do here

Answer 11

graph if cool
http://www.wolframalpha.com/input/?i=sqrt%28%287xcos%28x%29%29^2%2B%28-7xsin%28x%29%2B14cos%28x%29%29^2%29

Answer 12

*is

Answer 13

r(t)=(7tsint+7cost)i + 7j + (7tcost-7sint)k, Find the Tangential, Normal, Binormal, and the Torsion.

Answer 14

I think that's as far as it's going to go if I pull out the 49.

Answer 15

tangential is just ...
\[|r'(t)| \text{ }\]
\[r'(t)=[7 \sin(t)+7t \cos(t)-7\sin(t)]i+[0]j+[7 \cos(t)-7 t \sin(t)-7 \cos(t)]k \\ r'(t)=7 t \cos(t) i -7t \sin(t) k\]

Answer 16

\[|r'(t)|=\sqrt{(7 t \cos(t))^2+(-7 t \sin(t))^2}\]

Answer 17

this looks prettier

Answer 18

wait hold on let me check your derivative because I checked mine like 4 times.

Answer 19

it looks like your k component was different

Answer 20

yeah seems like you wrote 7cos(t)-7 cos(t) as 7 cos(t)+7 cos(t) instead

Answer 21

ahhhhhhhh i screwed up the last part!!!!!

Answer 22

thanks freckles.

Answer 23

np

Answer 24

derivative of -7sint = 7cost <--- lmfao i'm an idiot.

Answer 25

maybe for a sec you got antiderivative and derivative mixed up :p it happens to all of us especially on those crazy trig functions

Answer 26

It happens to me all the time.

Answer 27

I've been doing way too many integrals

Answer 28

anyways glad i can help

Answer 29

see ya man thx again!

Answer 30

peace