Hello, I am stuck on this question - please refer to the attachment.
Are you allowed to just get rid of the t^2 + 1 (by multiplying to the other side, which equals 0) ??? I remember my maths teacher telling me you cannot get rid of an unknown variable (in this case, that would be 't') when calculating f'(x) = 0. So how come it does that in the worked solution?
Are you allowed to just get rid of the t^2 + 1 (by multiplying to the other side, which equals 0) ??? I remember my maths teacher telling me you cannot get rid of an unknown variable (in this case, that would be 't') when calculating f'(x) = 0. So how come it does that in the worked solution?