Oblicz:a=32cos20xcos40xcos80
Oblicz:a=32cos20xcos40xcos80
a=32cos20*cos40*cos80= 32*cos20*cos40*cos80*2sin20 ________________________ = 2sin20 32* sin40 *cos40* cos80 ______________________ = 2sin20 16* 2sin40*cos40 *cos80 ____________________ = 2sin20 16* sin80 * cos80 _______________ = 2sin20 8*2sin80*cos80 _____________ = 2sin20 8sin160 _______ = 2sin20 8sin (180-20) ___________ = 2sin20 8sin20 ______ = 8/2 = 4 2sin20