Question

тригонометрические функции. упростить выражения

Answer 1

$1)1-cos^2t=sin^2t \ \ 2)sin^2t-1=sin^2t-(sin^2t+cos^2t)=sin^2t-sin^2t-cos^2t=-cos^2t \ \ 3)(1-cost)(1+cost)=1-cos^2t=sin^2t \ \ 4)sin^2t+2cos^2t-1=sin^2t+2cos^2t-(sin^2t+cos^2t)=sin^2t+2cos^2t$$-sin^2t-cos^2t=cos^2t$

Answer 2

спасибо