My 1/2 question thread

[pi]

^^Nice

[tony3272]

Edit:wtf i can tweet, share, google+ and like my AN post?

Lol what's up with that 

[Truck]

kinda hijacking his thread, but the question is in the same topic soooo...

anyone able to solve;

cos^2(2x) + 2cos(4x)=-1  ,x element of [-pi, 3pi/2]

[WhoTookMyUsername]

URGENT HELP !!!! NEED ANSWER ASP lol

r^2 (sin2x + cos2x) = 3
(x = theta)


where
r = root (x^2 + y^2)
How do you put that in cartesian?


thanks a lot

[WhoTookMyUsername]

Another question
Determine the locus of a point P which moves so that the difference of the squares of its distances from two fixed points P1(4,0) and P2(-4,0) is constant

[WhoTookMyUsername]

The resultant force when two forces of magnitude 20 kg wt and 20 kg wt act at an angle 60 to each other.
The resultant force is?


(tried everything but can't get right answer!)

[WhoTookMyUsername]

urgent help! i know your all busy, but if anyone doing 1/2, or any person doing 3/4 is kind enough to help would be much appreciated with questions 8, 11, 12, 13

thanks a lot! (pdf attached)

[xZero]

I'll do q8, if i have time tonight I'll have a look at the rest

8 ) there's 2 initial approach, do which ever that suits you the most

approach 1)


, well how the hell do you square root that? simple, all you have to do is write in terms of





 













, ignore the negative because from , we implied that x and y are integers, even if you take the negative root, your final solution will be the same



, again take negative or positive, still gets you the same solution, in this case i chose positive to keep things neat











approach 2, let , expand LHS, equate all the coefficients and you'll get to the same quadratic equations but in terms of c and d

[WhoTookMyUsername]

thanks a ton xZero!
great explanation for question 8
(if you could manage to do the other 3 some time soonish that would be awesome)
much appreciated

[xZero]

ceebs with 12 and 13... cant take any more physics

11) a)
OK=OR+RK
=OS+SK
=OS-KS, if PK=nPS then KS=(1-n)PS
=OS-(1-n)PS
=OS-(1-n)(-OP+OS)
=OS+(1-n)OP-(1-N)OS
=(1-n)OP+nOS
=(1-n)p+2nr

for the second part of part a), just do the same thing but with OQ and QK, see if you can do it

b)
equate the 2 equations you found in part a), the solution should be n=1/4 and m=1/2

[WhoTookMyUsername]

thanks xZero,
i did a similar thing with OQ and QK, but i'm not sure what to do when i equate the 2 equations? i just get a bunch of random letters in terms of n, m, p etc.

any chance you could show me

thanks!

EDIT: worked out thanks