AP EAMCET2009MathematicsStraight Lines
The transformed equation of x^2+y^2=r^2 when the axes are rotated through an angle 36^ is
Options
- A5 X^2-4 X Y+Y^2=r^2
- BX^2+2 X Y- 5 Y^2=r^2
- CX^2-Y^2=r^2
- DX^2+Y^2=r^2
Correct answer
D. X^2+Y^2=r^2
Step-by-step solution
Given equation is x^2+y^2=r^2 . After rotation aligned & x=X 36^ -Y 36^ & and y=X 36^ +Y 36^ & X^2 ( ^2 36^ + ^2 36^ ) & & Y^2 ( ^2 36^ + ^2 36^ )=r^2 & X^2+Y^2=r^2 aligned