C4 differentiation

think about this a little more, the gradient when t=0 is 0.

so the gradient of the normal is -(1/0), which is infinity.

So when you think about it, when t=0 the tangent to the curve is a horizontal line, so the normal must be a vertical line.

(You can't use the equation you stated as that uses the gradient of the normal which is undefined (assumed infinity))

(You got y=2 because you used the gradient of the tangent )

Oh i get it but i still don't understand why they said it's x=1, i get that we know the normal is vertical but why do we assume its x=1

because when t=0, x = e^0, which is 1

the normal still has to pass through the same point remember

OH yeah! Thanks