Hi to all..(adsbygoogle = window.adsbygoogle || []).push({});

I am doing Phd in bioinformatics, having little knowledge abt maths..

I have calculated Phi Psi angles(dihedral angle)between two planes...

But the thing is i didnt get proper sign for my result(may be + or -).

I used following formulae for calculate the dihedral angle between two planes...

cos(theta)=(A.B/|A||B|)

any one help me how can i get the signed values for my result..

my program value..

theta=cos inverse of (-0.717563607965311)

theta=135.9,

But i need the result as -135.9

tanks in advance...

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# Regarding signed dihedral angle doubt

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