Given line equation of 2-order: 9x2+121y2−1089=0 This equation looks like: a11y22+2a12x2y2+2a13y2+a22x22+2a23x2+a33=0 where a11=0 a12=0 a13=2121 a22=0 a23=29 a33=−1089 To calculate the determinant Δ=a11a12a12a22 or, substitute Δ=0000 Δ=0 Because Δ is equal to 0, then Given equation is straight line - reduced to canonical form The center of the canonical coordinate system in OXY y20=−x~2sin(ϕ)+y~2cos(ϕ) x20=x~2cos(ϕ)+y~2sin(ϕ) y20=0⋅0 x20=0⋅0 y20=0 x20=0 The center of canonical coordinate system at point O
(0, 0)
Basis of the canonical coordinate system e1=(1,0) e2=(0,1)
Invariants method
Given line equation of 2-order: 9x2+121y2−1089=0 This equation looks like: a11y22+2a12x2y2+2a13y2+a22x22+2a23x2+a33=0 where a11=0 a12=0 a13=2121 a22=0 a23=29 a33=−1089 The invariants of the equation when converting coordinates are determinants: I1=a11+a22
I1=0 I2=0 I3=0 I(λ)=λ2 K2=−27361 Because I2=0∧I3=0∧(I1=0∨K2=0) then by line type: this equation is of type : two coincident straight lines I1x~22+I1K2=0 or