Ответ:
Объяснение:
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<span><span><span>х²-3х-40=0
</span></span></span>х₁+х₂=3 -- <span>теорема Виета</span>
х₁х₂= - 40
х₁=8
х₂= - 5
Решение
<span>sin2</span>π<span>/5+sin</span>π<span>/5 = 2sin</span>π/5*cosπ/5 + sinπ/5 = sinπ/5 * (2cosπ/5 + 1)