Ребят помогите плиззз не черта не получается!)определите знак произведения:
a)sin210<span><span>°<em />sin465<span><span>°cos539<span><span>°; б)</span></span><span><span /></span></span></span><span><span><span><span>cos375<span><span>°sin231<span><span>°tg410<span><span>°ctg609<span><span>°</span></span></span></span></span></span></span></span></span></span></span></span></span></span>
a)sin210<span><span>°<em />sin465<span><span>°</span></span><span><span>cos539</span></span><span><span><span><span>°=- + - =+</span></span></span></span></span></span>
<span><span><span><span><span><span>б)</span></span></span></span><span><span><span><span>cos375<span><span>°sin231<span><span>°tg410<span><span>°ctg609<span><span>°=+ - + += -</span></span></span></span></span></span></span></span></span></span></span></span></span></span>
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!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!