а) = tq²α*sin²α/(tq²α -sin²α) =cos²α*tq²α*sin²α/sin²α(1 -cos²α)=sin²α*sin²α/sin²α*sin²α =1.
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б) =( tqα/(1-tq²α)) * ((ctq²α -1)/ctqα )= (1/2)*tq2α* 2ctq2α =1.
5.72^2 - 4.6 * 0.72 - 1.12 * 5.72 = 5.72^2 - 1.12 * 5.72 - 4.6 * 0.72 = 5.72*(5.72 - 1.12) = 5.72 * 4.6 - 4.6 * 0.72 = 4.6 * (5.72 - 0.72) = 4.6 * 5 = 23