Can someone help me with this:
Find all solutions in the interval [0, 2pi) .
7 tan^3x - 21 tan x = 0

Question

Can someone help me with this:
Find all solutions in the interval [0, 2pi) . 
 7 tan^3x - 21 tan x = 0

danjs · Answer

try factoring tan(x) out first, so tan(x) = 0,  recall identities to replace tan^2 and tan by sin and cos maybe

danjs · Answer

those probs just play around till you get something in terms of sin and cos using identities and algebra

danjs · Answer

$$7\tan(x)[\tan^2(x) -3]=0$$

$$7\tan(x)[\frac{ \sin^2(x) }{ \cos^2(x) } -3]=0$$

anonymous · Answer

Here

anonymous · Answer

On the very left its pie.k and not pie

anonymous · Answer

@DanJS what are you doing ? :s

anonymous · Answer

I mean very right* on the bottom +pie.k

danjs · Answer

lol idk, you have it right,

use the unit circle, tan(x)=y/x,   remember symmetries if needed for multiple answers over the domain

anonymous · Answer

Thats better

danjs · Answer

looks right

anonymous · Answer

Oh and since its limited between ]0,2pie[
Then you write my answer and add for k=0,1,2