№26.13(а),
№26.16(б),
№26.17(б)
26.13 tg(<span>π-t) / cos(<span>π+t) * sin 3<span>π/2+t) / tg(3<span>π</span>/2+t) = -tg(t) / - cos(t) * - cos(t) / - ctg(t) = tg (t) / ctg (t) = tg^(t)</span></span></span>
<span><span><span>26.16 cos125*cos5 + sin55*cos85 = cos (180-55) * cos (90 - 85) * sin55 cos85 = - cos55 * sin85 - cos55 * sin95 = sin (55 - 85) = - sin30 = - 1/2</span></span></span>