- #1
skyturnred
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Homework Statement
The point is (0, -8, 0)
r≥0
0≤θ≤2∏
0≤[itex]\varphi[/itex]≤∏
Homework Equations
The Attempt at a Solution
So here is what I've done so far:
I know that r=8 because x and z are 0
I know that θ=∏/4 or 3∏/4, but which one? both of these satisfy the following equation (which is the only one I know for this)
cos(θ)=y/x
Also, I am confused about [itex]\varphi[/itex]. I know that:
tan([itex]\varphi[/itex])=y/x, but y is negative, and x is zero. I know the value of arctan(∞) as well as arctan(-∞) but which one do I use? I am so confused. Thanks!