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AP EAMCET · Maths · Straight Lines

When the coordinate axes are rotated by an angle tan-134 about the origin, then the equation x2+y2=9 is transformed to the equation

  1. A x2-y2=9
  2. B x2+y2+2xy=4
  3. C x2+y2=9
  4. D x2-y2+9=0
Verified Solution

Answer & Solution

Correct Answer

(C) x2+y2=9

Step-by-step Solution

Detailed explanation

Let θ be the angle of rotation, then θ=tan-134. Now, new coordinate axes are X=xcosθ-ysinθ Y=xsinθ+ycosθ Then, X=xcostan-134-ysintan-134 Y=xsintan-134+ycostan-134 Or X=x45-y35 Y=x35+y45 On solving, we get x=4X+3Y5 y=4Y-3X5 Now, putting these values…