trygonometria antek: OBLICZ 8sin555*sin255

Monika: 8sin(555)*sin(255) = 8sin(540+15)*sin(180+75) = 8 *(−cos15)* (−sin 75) = 8 cos(45−30)*sin(45+30) =8*(cos45cos30−sin45sin30)(sin45cos30+sin30cos45) =8*(^√2₂*^√3₂ − ^√2₂*¹₂)(^√2₂*^√3₂ + ^√2₂*¹₂) =8*(^√6₄−^√2₄)(^√6₄+^√2₄) =8*(^{(√6−√2)*(√6+√2)}₁₆) = ⁶⁻²₂ = 2