214 f(x)=√x-1  g(x)=√3-x F=f+g={√ x-1+√3-x} D(F)={√ x-1+√3-x}⇔{ x≥1, x≤3}⇒ D(F)=[1;3] բ)F=f-g=√x-1-√3-x D(F)={√ x-1+√3-x}⇔{ x≥1, x≤3}⇒ D(F)=[1;3] գ)F=f*g=√ x-1*√3-x D(F)={√ x-1*√3-x}⇔{ x≥1, x<3}⇒ D(F)=[1;3] դ)F=f/g=√ x-1/√3-x D(F)={x-1≥0, 3-x≥0, 3-x≠0⇔{ x≥1, x<3}⇒D(F)=(1;3] 215   f(x)=1+x² g(x)=1/1-x F=fºg F=1+(1/1-x)²=(1-x)²+1/(1-x)²=1-2x+x²+1/(1-x)²=x²-2x+2/(1-x)²