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# Solutions to cotx=0 watch

1. Are there any solutions for cotx=0, because that means 1/tanx=0, and rearranging will give 1=0, so I didn't think this was possible. But the graph of cotx intercepts the x axis, so im kind of confused.
2. cotx = 1/tanx = cosx/sinx = 0...
3. cotx = cosx/sinx so if cotx = 0, cosx must =0

arccos 0 = pi/2 etc.
4. Replace cotx with cosx/sinx.
5. Yes, wherever tan(x) is infinity, then cot(x)=0. But we're not allowed to discuss the exam....
6. (Original post by zafaru123)
Are there any solutions for cotx=0, because that means 1/tanx=0, and rearranging will give 1=0, so I didn't think this was possible. But the graph of cotx intercepts the x axis, so im kind of confused.
I think that's a false move. You can't move 0 down, coz in effect you are dividing by 0 on both sides. And dividing by 0 is not allowed.
7. 1/tanx=0

tanx=0 .....
8. Cotx= 1/tanx

= 1/ (sinx/cosx)
=cosx/sinx = 0

=> cos x = 0.
9. Im wondering about this aswell, on the cot graph, it does cross the x axis, but if you look at it in terms of tan, its impossible.
10. You must be drawing the graph wrong. http://www4c.wolframalpha.com/Calcul...image/gif&s=22

I think you may also be looking at x=0 which does indeed have no value.
11. I've done this in a past paper.
If cotx = 0, then tanx ---> infinity. (tanx tends to infinity)
So, the solutions will be 90, 270 etc. (wherever the tan graph lines go to asymptotes).

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