A curiosity I've had recently...(adsbygoogle = window.adsbygoogle || []).push({});

When repeatedly taking the cosine of a number in radians, it appears to converge to a value.

i.e. cos(cos(cos(...cos(x)...))) = 0.73908513321516064165531208767387...

Any thoughts/explanations/exact solution etc?

Thanks.

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# Repeatedly 'cosine'ing a number: convergence

**Physics Forums | Science Articles, Homework Help, Discussion**