663) Lim(tqx-tqx)/(x-x₁) =Lim ( sin(x-x₁)/(x-x₁)*(1/(cosx*cosx₁) = 1/cos²x₁ ;
[ Вместо Xo обоз. x₁ ] .
664) Lim(sinx - cosx)/(x-π/4) = Lim(√2sin(x-π/4)/(x-ππ/4) =√2 .
665) Lim(cosx)/(π -2x) =1/2*Limsin(π/2 -x)/(π/2-x) =1/2*1 =1/2.
666) Lim(2x^4+3x²+5x-6/(x³ +3x² +7x -1) =
=Lim(2*x+3/x +5/x² 6/x³)/(1+3/x+7/x²-1/x³) = ∞ .