Ответ:
Вариантов масса, один из них: a = 90, a = 45.
Объяснение:
НОК 90 и 90 = 90,
НОК 45 и 90 = 90.
<span>√у=1.9
у=1.9</span>²
у= 3,61.........................................
Упростить выражение (sin232° +cos142° +2)/cos128° .
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(sin232° +cos142° +2)/cos128° =(sin270°-38°) +cos(180° -38°+2)/cos(90°+38°)
= (-cos38°- cos38°+2)/(-sin38°) = - 2(1 - cos38°)/sin38°= - 4sin²19°/2sin19°*cos19° =
= -2tq19° .
cos(π/7)+cos(π/15)= 2cos((π/7+π/15)/2)*cos((π/7-π/15)/2)= 2cos(11π/105)*cos(4π/105)