4 ms·cos is not the inverse of sin, cos(sin(9)) is not 9by agravier 6y agocos is not the inverse of sin, cos(sin(9)) is not 9molyss 6y agoI think the intended simplification is : (sin⁻¹(cos⁻¹(tan⁻¹(tan(cos(sin(9))))))−9)⁻¹ -> (sin⁻¹(cos⁻¹(cos(sin(9))))−9)⁻¹ -> (sin⁻¹(sin(9))−9)⁻¹ -> (9−9)⁻¹ -> 0⁻¹ -> 1/0agravier 6y agoI see, right. This is curious.