i set the general point's modulus/magnitude/length equal to 2 then rearranged to get a polynomial function of lambda and used discriminant to show no real solutions for lambda therefore fish couldnt have travelled within 2 metre radius. though thats not in the mark scheme?
@customxcycles8090 Hm yeah that seems legit though, although since 10 days ago I've found a different way, just find 2 general points on the line, OA, and OB, then find the vector from a to b, and dot it with the vector CX (x being a gen point on the line and C being the point given) , then dot them and equal to 0, then sub the Lambda value you get into X and find the modulus of it
So using the cos theta formula finds the angle between two lines. However, you have the normal vector to the plane. So if you use the cos formula you end up finding a different angle to the one you need (you'd get 68.8) So two options, either do what I did and use the sin formula, or do 180-90-ans (in this case you can see we get 21.2). This is on page 186 of the textbook
