MAT2615
ASSINGMENT 2
2024
, QUESTION 1
Solution:
a).
f(x, y) = c
f(x, y) = c
1 + x2 + y2 = c ∴ x = 1 and y = 1
1 + (1)2 + (1)2 = c
c=3
f(x, y) = 3
1 + x2 + y2 = 3
x2 + y2 = 3 − 1
x2 + y2 = 2
2
x 2 + y 2 = (√2) a circle with center at origin and radius √2
2
Equation of Curve C: x 2 + y 2 = (√2)
, b).
⃗ = vector that is perpendicular to C at (1,1)
Let: n
⃗ = 〈fx (1,1), fy (1,1)〉
n
f(x, y) = 1 + x 2 + y 2
fx (x, y) = 2x and fy (x, y) = 2y
fx (1,1) = 2(1) and fy (1,1) = 2(1)
fx (1,1) = 2 and fy (1,1) = 2
⃗ = (fx (1,1), fy (1,1))
n
⃗ = (2,2)
n
c).
Equation of line: (x, y) = (xo , y0 ) + tn
⃗
(x, y) = (xo , y0 ) + tn
⃗ ∴ (xo , y0 ) = (1,1)
(x, y) = (1,1) + t(2,2)
(x, y) = (1 + 2t, 1 + 2t)
x = 1 + 2t and y = 1 + 2t
x−1 y−1
t= and t =
2 2
x−1 y−1
=
2 2
ASSINGMENT 2
2024
, QUESTION 1
Solution:
a).
f(x, y) = c
f(x, y) = c
1 + x2 + y2 = c ∴ x = 1 and y = 1
1 + (1)2 + (1)2 = c
c=3
f(x, y) = 3
1 + x2 + y2 = 3
x2 + y2 = 3 − 1
x2 + y2 = 2
2
x 2 + y 2 = (√2) a circle with center at origin and radius √2
2
Equation of Curve C: x 2 + y 2 = (√2)
, b).
⃗ = vector that is perpendicular to C at (1,1)
Let: n
⃗ = 〈fx (1,1), fy (1,1)〉
n
f(x, y) = 1 + x 2 + y 2
fx (x, y) = 2x and fy (x, y) = 2y
fx (1,1) = 2(1) and fy (1,1) = 2(1)
fx (1,1) = 2 and fy (1,1) = 2
⃗ = (fx (1,1), fy (1,1))
n
⃗ = (2,2)
n
c).
Equation of line: (x, y) = (xo , y0 ) + tn
⃗
(x, y) = (xo , y0 ) + tn
⃗ ∴ (xo , y0 ) = (1,1)
(x, y) = (1,1) + t(2,2)
(x, y) = (1 + 2t, 1 + 2t)
x = 1 + 2t and y = 1 + 2t
x−1 y−1
t= and t =
2 2
x−1 y−1
=
2 2