Question 1022246
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cos beta=0.4, find the value of cos beta +cos(beta+2pi)+cos(beta+4pi)
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{{{cos(beta + 2*pi)}}} = {{{cos(beta)}}};


{{{cos(beta+4*pi)}}} = {{{cos(beta)}}}.


Therefore 


{{{cos(beta)}}} + {{{cos(beta+2pi)}}} + {{{cos(beta+4pi)}}} = {{{3*cos(beta)}}}.