roselin
explain why the equation cox=x has at least one solution.
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zepdrix
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cox???
roselin
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sorry,sorry. its cos x
zepdrix
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oh lol ^^
zepdrix
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Hmm do you remember what the graph for cosine looks like?
roselin
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somewhat
baldymcgee6
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I'm pretty sure cos(x) = x only has one solution
zepdrix
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|dw:1351373928927:dw|
This is kind of the idea rose :D At this particular point, the x value and the cosx value are the same.
roselin
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|dw:1351373944681:dw|
zepdrix
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So in your picture, x=pi/2
but cosx = 0
Hmm that point doesn't work so well :c
roselin
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okay, i will consider the picture that you showed
zepdrix
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Yah I can't think of the proper way to explain it :D It probably has something to do with the fact that cosine oscillates back and forth between 1 and -1, and since it is continuous it would have to have a solution :d i dunno... just think about it i guess :3 heh
baldymcgee6
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Since the function y = x has a domain of all real numbers... as is cos(x), there must be a point of intersection somewhere
roselin
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okay,
roselin
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So which one should I consider now? i have two answers here
baldymcgee6
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Combine them... you could say..
Since both y=x and the cosine function have a domain of all real numbers and both are continuous at least one point of intersection is definite.
roselin
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oh okay, thank you so much guys
Zarkon
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use the intermediate value theorem
latremese40
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roelin i think you did it right