admin百科知識 2022-02-12 21:35:08 已知cos(x+π12)=13,則sin(2x-π3)的值爲多少?已知cos(x π/12)=1/3,則sin(2x-π/3)的值爲多少?網友廻答：匿名網友已知cos(x π/12)=1/3,那麽：cos(2x π/6)=2cos²(x π/12)-1=2/9 - 1=-7/9所以：sin(2x-π/3)=sin[(2x π/6)- π/2]=-sin[π/2 -(2x π/6)]=-cos(2x π/6)=7/9 db標簽 生活常識_百科知識_各類知識大全»已知cos(x+π12)=13,則sin(2x-π3)的值爲多少?
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