I'm trying to find a value K>o such that for real a,b,c,d(adsbygoogle = window.adsbygoogle || []).push({});

(a^2+c^2)x^2+2(ab+cd)xy+(b^2+d^2)y^2 ≤ K(x^2+y^2).

Any help on this would be greatly appreciated thanks.

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# Need help finding a bound for an equation

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