Question

sin105°cos15°+sin15°sin165°+tg225°;
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Answer 1

$Sin105^{o}Cos15^{o}+Sin15^{o}Sin165^{o}+tg225^{o}=Sin(90^{o}+15^{o})Cos15^{o} +Sin15^{o}Sin(180^{o} -15^{o})+tg(180^{o}+45^{o} )=Cos15^{o}Cos15^{o}+Sin15^{o}Sin15^{o}+tg45^{o}=Cos^{2}15^{o}+Sin^{2}15^{o}+tg45^{o}=1+1=2$