
Solving a trig equation?
I need to solve the following trig expression:
4cos4θ=0 (reads four cosine four theta)
Its the formula of a graph but i need to find the zeros or the points that it passes through the pole (its a polar graph)
Would i use the double angle formula or find when cos=0 and multiply the period by 4? Im confused(Worried)

I think you are making this more difficult than it really is....
4cos4θ=0
the four is insignificant (because 0/4 is still 0). so now we have:
cos4θ=0.
I think the 4 is confusing you so let x=4θ so now we have:
cosx=0
and the solutions to that is when x=pi/2 or 3pi/2
now substitute 4θ in for x and you have
4θ=pi/2 and 4θ=3pi/2
so dividing by four yields:
θ=pi/8 and θ=3pi/8
Hope that helped!!

Also what domain are you looking for solutions in?
The previous post gives the solutions on $\displaystyle x \in \left[0,\frac{\pi}{2}\right]$
You can find all solutions as $\displaystyle x = \frac{(2n+1)\pi}{8}, n\in \mathbb{Z}$