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Could you help me to find a quotient mapping from $\mathbb R^2$ onto $\mathbb R^2\setminus \{(0,0)\}$?

Assume the standard topology on both spaces.

Thank you.

share|cite|improve this question
Hint: polar coordinates. – Qiaochu Yuan May 12 '12 at 19:01
Do you know any complex analysis? Especially -- hint! -- do you know about the complex exponential function? – Pete L. Clark May 12 '12 at 19:01

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