Quote:
Originally Posted by magmagod
So the question is basically solve each equation for 0<x<2pi...i just have trouble with isolating the equations for the following:
- square root 2 sinx = 2sinx cos x
- 2cosx - 3/cosx + 2 square root2 = 0
for the first one i got this far:
square root 2 sinx = 2sinx (double angle)
squared both sides and ended with 2 sinx = 4 sin^2x
divided by 2 sinx to both sides and got 1 = 2 sinx
then i isolated for sinx ... sinx = 1/2
is it right so far? then i just found the related acute angle and the values in Q 1 and 3
I appreciate your help so far  i will try and help you with your problems.. |
Wow, these are tough problems the way you have presented them. Maybe you have left out some parentheses or something.
For the 1st one, I am assuming that first dash is NOT a negative sign, therefore:
sinx*sqrt(2) = 2sinxcosx
sqrt(2) = 2cosx
sqrt(2)/2 = cosx
Taking the inverse cos of both sides gives
x = pi/4 and 7*pi/4
If the first dash is a negative sign, then x = 3*pi/4 and 5*pi/4.
Your solution is incorrect because 2sinxcosx = sin2x, not 2sinx.