-
Best of luck to the class of 2024 for their HSC exams. You got this! Let us know your thoughts on the HSC exams here -
YOU can help the next generation of students in the community! Share your trial papers and notes on our Notes & Resources page
another trig question (1 Viewer)
- Thread starter alez
- Start date
P
pLuvia
Guest
You can't just divide by 2tanx, that would mean you are eliminating one of the solutions.
Better way would be to factorise it then you'll get your answer
The answer is 0, pi, 2pi, 3pi. Depending on the domain of the function, the answers could go on forever
Better way would be to factorise it then you'll get your answer
The answer is 0, pi, 2pi, 3pi. Depending on the domain of the function, the answers could go on forever
Last edited by a moderator:
conics2008
Active Member
- Joined
- Mar 26, 2008
- Messages
- 1,228
- Gender
- Male
- HSC
- 2005
Hi there, I speak English.
3tan(2x)=2tan(x) >> Use The double angel shit tan(2x) = 2tan(x)/1-tan^2(x)
3(2tan(x)/1-tan^2(x)) = 2tan(x) >> take away the base
6tan(x)=2tan(x)-2tan^3(x) >> collect like terms
4tan(x)+2tan^3(x)=0 >> now you can see x = 0 is a root.
but when you factorise the get shit out of it, you get something like tan^2(x)=-2
now you cant square root a negative number right ? so you ignore it since its not REAL ( wow I feel soo big saying this word REAL )
ok so you know tan(x)=0 >>> the thing with trig is that it can have alot of roots
now look for values that make tan(x) =0
in the 1st quadrant and in the 3rd right ? 3rd Quad uses 180+Theta
therefore roots are
0,180 for the first revolution
then 360,540 2nd revolution and so on..
how I got 360 I do this, see the first 2 rounds you got 0 and 180 soo when you start another revoultion you do
360+0 , 360 + 180 and so on...
GOOD LUCKKKKKKKKK .. I speak english
3tan(2x)=2tan(x) >> Use The double angel shit tan(2x) = 2tan(x)/1-tan^2(x)
3(2tan(x)/1-tan^2(x)) = 2tan(x) >> take away the base
6tan(x)=2tan(x)-2tan^3(x) >> collect like terms
4tan(x)+2tan^3(x)=0 >> now you can see x = 0 is a root.
but when you factorise the get shit out of it, you get something like tan^2(x)=-2
now you cant square root a negative number right ? so you ignore it since its not REAL ( wow I feel soo big saying this word REAL )
ok so you know tan(x)=0 >>> the thing with trig is that it can have alot of roots
now look for values that make tan(x) =0
in the 1st quadrant and in the 3rd right ? 3rd Quad uses 180+Theta
therefore roots are
0,180 for the first revolution
then 360,540 2nd revolution and so on..
how I got 360 I do this, see the first 2 rounds you got 0 and 180 soo when you start another revoultion you do
360+0 , 360 + 180 and so on...
GOOD LUCKKKKKKKKK .. I speak english
~Fire Jade~
Member
I hope this doesn't confuse you even more than you already are...
I think this is how you do it....
3tan2x=tanx
Use the double angle formula crap
3[(2tanx)/(1-tan^2x)]=tanx
Move the bottom thingo on the LHS to the RHS...and u end up with something like this...
6tanx=tanx (1-tan^2x)
u expand it
6tanx=tanx- tan^3x
0=tan^3x+ 5tanx
Factorise it
0=tanx(tan^2x+5)
Solun:
tanx=0 or tan^2x=-5 (no solun??)
Solve it from there
:burn:
I don't know whether this is right and I take no responsibility for this junk if its wrong. lols.:rofl:
I think this is how you do it....
3tan2x=tanx
Use the double angle formula crap
3[(2tanx)/(1-tan^2x)]=tanx
Move the bottom thingo on the LHS to the RHS...and u end up with something like this...
6tanx=tanx (1-tan^2x)
u expand it
6tanx=tanx- tan^3x
0=tan^3x+ 5tanx
Factorise it
0=tanx(tan^2x+5)
Solun:
tanx=0 or tan^2x=-5 (no solun??)
Solve it from there
:burn:
I don't know whether this is right and I take no responsibility for this junk if its wrong. lols.:rofl: