Question

задания в прикреплены

Answer 1

458.

$tg(a+b)=frac{tga+tgb}{1-tgatgb}=frac{frac{4}{3}+frac{1}{4}}{1-frac{4*1}{3*4}}=frac{19}{8}.$

 

439.

$sqrt{2}sin(frac{pi}{4}+a)-cosa=cosa+sina-cosa=sina.$

б) $sqrt{2}sin(a-frac{pi}{4})-sina=sina-cosa-sina=-cosa.$

в) $2cos(frac{pi}{3}-a)-sqrt{3}sina=cosa+sqrt{3}sina-sqrt{3}sina=cosa.$

г) $sqrt{3}cosa-2cos(a-frac{pi}{6})=sqrt{3}cosa-sqrt{3}cosa-sina=-sina.$

 

445.

а) $cos18cos63+sin18sin63=cos(18-63)=cos45= frac{sqrt{2}}{2}.$

б) cos32cos58-sin32sin58=$cos32cos58-sin32sin58=cos(32+58)=cos90= 0.$