Question

Упростите выражение (sin232+cos142+2)\cos128

Answer 1

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° .