Question

Упростить:

1+ctg(3p/2+a)sina * cosa - cos^2a

Answer 1

$1 + ctg( frac{3pi}{2} + alpha ) times sin alpha times cos alpha - {(cos alpha )}^{2} = \ = 1 - tg alpha times sin alpha times cos alpha - {(cos alpha )}^{2} = \ = 1 - frac{sin alpha }{cos alpha } times sin alpha times cos alpha - {(cos alpha )}^{2} = \ = 1 - {(sin alpha )}^{2} - {(cos alpha )}^{2} = 1 - ( {(sin alpha )}^{2} + {(cos alpha )}^{2}) = \ = 1 - 1 = 0$



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