If sin^-1 ⁡a is the acute angle between the curves x^2+y^2=4x and x^2+y^2=8 at (2 ,2 ), then a=

Question

Accepted Answer

Correct answer: C. (c) : Slope of first curve m_1=0; slope of second curve m_2=-1; therefore angle is 45^ . a= sin ⁡45^ = 1 2

$If sin^{- 1} a is the acute angle between the curves x^{2} + y^{2} = 4 x and x^{2} + y^{2} = 8 at (2, 2), then a =$