Line Points Distance C7B14E
1. **Problem statement:**
We have a line 𝓛 defined by parametric equations:
$$x = 3 + 2t, \quad y = 2t, \quad z = t$$
and a point \(A(3,0,0)\).
(a) Prove that \(A\) is on 𝓛.
(b) Find two points \(E\) and \(F\) on 𝓛 each at distance 6 from \(A\).
2. **Step (a): Prove that A is on 𝓛**
To check if \(A(3,0,0)\) lies on 𝓛, we need to find a parameter \(t\) such that:
$$3 + 2t = 3, \quad 2t = 0, \quad t = 0$$
From \(2t=0\), we get \(t=0\).
Substitute \(t=0\) into \(x\) and \(z\):
$$x = 3 + 2(0) = 3, \quad z = 0$$
All coordinates match \(A\), so \(A\) is on 𝓛 at \(t=0\).
3. **Step (b): Find points E and F on 𝓛 at distance 6 from A**
Let a point on 𝓛 be \(P(t) = (3+2t, 2t, t)\).
Distance from \(A(3,0,0)\) to \(P(t)\) is:
$$d = \sqrt{(3+2t - 3)^2 + (2t - 0)^2 + (t - 0)^2} = \sqrt{(2t)^2 + (2t)^2 + t^2}$$
Simplify inside the square root:
$$= \sqrt{4t^2 + 4t^2 + t^2} = \sqrt{9t^2} = 3|t|$$
Set distance \(d=6\):
$$3|t| = 6 \implies |t| = 2$$
So \(t = 2\) or \(t = -2\).
Calculate points:
- For \(t=2\):
$$E = (3 + 2(2), 2(2), 2) = (7, 4, 2)$$
- For \(t=-2\):
$$F = (3 + 2(-2), 2(-2), -2) = (-1, -4, -2)$$
**Final answers:**
- (a) \(A(3,0,0)\) is on 𝓛 at \(t=0\).
- (b) Points \(E(7,4,2)\) and \(F(-1,-4,-2)\) lie on 𝓛 and are each 6 units from \(A\).