Question

Ajutatima si pe mine va rog cu problema asta, am fost atent in clasa online dar tot nu inteleg. ​

Answer 1

Răspuns:

Explicație pas cu pas:

cosa=-2√2/3   sina=1/3          tga=1/3:(-2√2)/3=-1/2√2=-√2/4

cosb=1/5           sinb=-2√6/5   tgb=-2√6/5:1/5=-2√6

sin(a-b)=sinacosb-cosasinb=1/3×1/5-(-2√6/5)(-2√2/3)=1/15-4√3/15=

          =(4√3-1)/15

cos(a+b)=-2√3/3×1/5-1/3(-2√6/5)=(-2√3+2√6)/16=-2√2(√3-1)/15

tg(a+b)=(tga+tgb)/(1-tgatgb)=(-√2/4-2√6)/(1-√2/4×2√6)=-√2(1/4+2√3)/(1-√3)=

           =-√2(1+8√3)/4:(1-√3)=-√2(1+8√3)(1+√3)/4×(-2)=√2(25+11√3)/8

tg(a-b)=sin(a-b)/cos(a-b)=-2√2(1+√3)/15:-2√2(√3-1)/15=(√3+1)/(√3-1)