AP EAMCET202422 May 2024Evening ShiftMathematicsHyperbolaActual
The line 21 x+5 y=k touches the hyperbola 7 x^2-5 y^2= 232 then k=
Options
- A116
- B232
- C58
- D110
Correct answer
A. 116
Step-by-step solution
The line A x+ B y+ C =0 touches the hyperbola x^2 a^2 - y^2 b^2 =1 if C ^2=a^2 ~A ^2-b^2 ~B ^2 ...(i) Now, given line is 21 x+5 y=k and hyperbola 7 x^2-5 y^2=232 x^2 ( 232 7 ) - y^2 ( 232 5 ) =1 So, from (i) we have k^2= 232 7 (21)^2- 232 5 (5)^2 k=116