Answer Check for Calculus Assignment

[menal]

http://i1183.photobucket.com/albums/x47 ... 4-7-69.gif

"Where should the point P be chosenon the line AB so as to maximize the angle theta"

i got .5279 as my answer..is that correct? ust want to know, if not then i will post how i got my answer, because it was pretty long.

 

[Deleted member 4993]

http://i1183.photobucket.com/albums/x476/Laura_Petrea/4-7-69.gif

"Where should the point P be chosenon the line AB so as to maximize the angle theta"

i got .5279 as my answer..is that correct? ust want to know, if not then i will post how i got my answer, because it was pretty long.

I do not understand your answer. You are given AP = 3 - where does 0.5279 come from?

 

[menal]

i did what this person did:

https://docs.google.com/viewer?a=v&pid= ... y=CKXgx40F

 

[Deleted member 4993]

You did not answer my question!

Oh that means you copied the answer from somebody!!

You just want to make sure you copied it correctly !!!

 

[menal]

uhm, no. i am going to have a similar question on my test so i wanted know and understand what this person did first so i could teach myself what to do for the test. Before you assume, you should clarify first.

 

[galactus]

Let x be the length of BP. Then, AP is 3-x.

\(\displaystyle \theta=\pi-cot^{-1}(\frac{3-x}{5})-cot^{-1}(\frac{x}{2})\)

This is what needs maximized.

\(\displaystyle \frac{d\theta}{dx}=\frac{-3x^{2}-12x+48}{x^{4}-6x^{3}+38x^{2}-24x+136}\)

\(\displaystyle -3x^{2}-12x+48=0\)

\(\displaystyle x=-2(\sqrt{5}+1), \;\ x=2(\sqrt{5}-1)\)

This leads to the same conclusion.