You can put this solution on YOUR website! find the exact value of cos (135+30)
use cos addition formula: cos(s+t)=cos s cos t-sin s sin t
cos 135=-√2/2
cos 30=√3/2
sin 135=√2/2
sin 30=1/2
cos(135+30)=cos135cos30-sin135sin30
=-√2/2*√3/2-√2/2*1/2
=-√6/4-√2/4
=-(√6+√2)4
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