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Copyright Β© 2011-2017 by Harold Toomey, WyzAnt Tutor 1
Haroldβs Precalculus Rectangular β Polar β Parametric
βCheat Sheetβ 15 October 2017
Rectangular Polar Parametric
Point
π(π₯) = π¦ (π₯, π¦) (π, π)
β’
(π , π) or π β π Point (a,b) in Rectangular: π₯(π‘) = π π¦(π‘) = π < π, π >
π‘ = 3ππ π£πππππππ, π’π π’ππππ¦ π‘πππ,
with 1 degree of freedom (df)
Polar Rect.
π₯ = π cos π π¦ = π π ππ π
π‘ππ π =π¦
π₯
Rect. Polar
π2 = π₯2 + π¦2
π = Β± βπ₯2 + π¦2
π = π‘ππβ1 (π¦
π₯)
Line
Slope-Intercept Form: π¦ = ππ₯ + π
Point-Slope Form:
π¦ β π¦0 = π (π₯ β π₯0)
General Form: π΄π₯ + π΅π¦ + πΆ = 0
Calculus Form:
π(π₯) = πβ²(π) π₯ + π(0)
< π₯, π¦ > = < π₯0, π¦0 > + π‘ < π, π > < π₯, π¦ > = < π₯0 + ππ‘, π¦0 + ππ‘ >
where < π, π > = < π₯2 β π₯1, π¦2 β π¦1 >
π₯(π‘) = π₯0 + π‘π π¦(π‘) = π¦0 + π‘π
π =βπ¦
βπ₯=
π¦2 β π¦1
π₯2 β π₯1=
π
π
Plane ππ₯(π₯ β π₯0)
+ππ¦(π¦ β π¦0)
+ ππ§(π§ β π§0) = 0
Vector Form: π β¦ (π β π0) = 0
π = π0 + π π + π‘π
Rectangular Polar Parametric .
Copyright Β© 2011-2017 by Harold Toomey, WyzAnt Tutor 2
Conics
General Equation for All Conics:
π΄π₯2 + π΅π₯π¦ + πΆπ¦2 + π·π₯ + πΈπ¦ + πΉ = 0
where πΏπππ: π΄ = π΅ = πΆ = 0 πΆπππππ: π΄ = πΆ πππ π΅ = 0 πΈπππππ π: π΄πΆ > 0 ππ π΅2 β 4π΄πΆ < 0 ππππππππ: π΄πΆ = 0 or π΅2 β 4π΄πΆ = 0 π»π¦πππππππ: π΄πΆ < 0 ππ π΅2 β 4π΄πΆ > 0 Note: If π΄ + πΆ = 0, square hyperbola
Rotation: If B β 0, then rotate coordinate system:
πππ‘ 2π =π΄ β πΆ
π΅
π₯ = π₯β² πππ π β π¦β² π ππ π π¦ = π¦β² πππ π + π₯β² π ππ π
New = (xβ, yβ), Old = (x, y)
rotates through angle π from x-axis
General Equation for All Conics:
π =π
1 β π πππ π
π€βπππ π = { π (1 β π2)
2π π (π2 β 1)
πππ { 0 β€ π < 1
π = 1π > 1
p = semi-latus rectum
or the line segment running from the focus to the curve in a direction parallel to the
directrix
Eccentricity: πΆπππππ π = 0πΈπππππ π 0 β€ π < 1ππππππππ π = 1π»π¦πππππππ π > 1
Rectangular Polar Parametric .
Copyright Β© 2011-2017 by Harold Toomey, WyzAnt Tutor 3
Circle
π₯2 + π¦2 = π2 (π₯ β β)2 + (π¦ β π)2 = π2
Center: (β, π) Vertices: NA Focus: (β, π)
(β, π)
Centered at Origin: r = a (constant)
π = π [0, 2π] ππ [0, 360Β°]
π₯(π‘) = π πππ (π‘) + β π¦(π‘) = π π ππ(π‘) + π
[π‘πππ, π‘πππ₯] = [0, 2π)
(β, π) = ππππ‘ππ ππ ππππππ
Rectangular Polar Parametric .
Copyright Β© 2011-2017 by Harold Toomey, WyzAnt Tutor 4
Ellipse
(π₯ β β)2
π2+
(π¦ β π)2
π2= 1
Center: (β, π)
Vertices: (β Β± π, π) and (β, π Β± π) Foci: (β Β± π, π)
Focus length, c, from center:
π = βπ2 β π2
Ellipse:
π =π (1 β π2)
1 + π πππ π πππ 0 β€ π < 1
π€βπππ π = π
π=
βπ2 β π2
π
relative to center (h,k)
Interesting Note: The sum of the distances from each focus
to a point on the curve is constant. |π1 + π2| = π
π₯(π‘) = π πππ (π‘) + β π¦(π‘) = π π ππ(π‘) + π
[π‘πππ, π‘πππ₯] = [0, 2π]
(β, π) = ππππ‘ππ ππ ππππππ π
Rotated Ellipse:
π₯(π‘) = π πππ π‘ πππ π β π π ππ π‘ π ππ π + β π¦(π‘) = π πππ π‘ π ππ π + π π ππ π‘ πππ π + π
π = the angle between the x-axis and the
major axis of the ellipse
Rectangular Polar Parametric .
Copyright Β© 2011-2017 by Harold Toomey, WyzAnt Tutor 5
Parabola
Vertical Axis of Symmetry: π₯2 = 4 ππ¦
(π₯ β β)2 = 4π(π¦ β π) Vertex: (β, π)
Focus: (β, π + π) Directrix: π¦ = π β π
Horizontal Axis of Symmetry:
π¦2 = 4 ππ₯ (π¦ β π)2 = 4π(π₯ β β)
Vertex: (β, π) Focus: (β + π, π)
Directrix: π₯ = β β π
Parabola:
π =2π
1 + π πππ π πππ π = 1
Trigonometric Form:
π¦ = π₯2 π π ππ π = π2 πππ 2 π
π =π ππ π
πππ 2 π= π‘ππ π π ππ π
Vertical Axis of Symmetry: π₯(π‘) = 2ππ‘ + β
π¦(π‘) = ππ‘2 + π (opens upwards) or π¦(π‘) = βππ‘2 β π (opens downwards)
[π‘πππ, π‘πππ₯] = [βπ, π] (h, k) = vertex of parabola
Horizontal Axis of Symmetry: π¦(π‘) = 2ππ‘ + π
π₯(π‘) = ππ‘2 + β (opens to the right) or π₯(π‘) = βππ‘2 β β (opens to the left)
[π‘πππ, π‘πππ₯] = [βπ, π] (h, k) = vertex of parabola
Projectile Motion: π₯(π‘) = π₯0 + π£π₯π‘
π¦(π‘) = π¦0 + π£π¦π‘ β 16π‘2 feet
π¦(π‘) = π¦0 + π£π¦π‘ β 4.9π‘2 meters
π£π₯ = π£ πππ π π£π¦ = π£ π ππ π
General Form:
π₯ = π΄π‘2 + π΅π‘ + πΆ π¦ = π·π‘2 + πΈπ‘ + πΉ
where A and D have the same sign
Rectangular Polar Parametric .
Copyright Β© 2011-2017 by Harold Toomey, WyzAnt Tutor 6
Hyperbola
(π₯ β β)2
π2β
(π¦ β π)2
π2= 1
Center: (β, π)
Vertices: (β Β± π, π) Foci: (β Β± π, π)
Focus length, c, from center:
π = βπ2 + π2
Hyperbola:
π =π (π2 β 1)
1 + π πππ π πππ π > 1
Eccentricity:
π€βπππ π = π
π=
βπ2 + π2
π= sec π > 1
relative to center (h,k)
p = semi-latus rectum or the line segment running from the focus
to the curve in the directions π = Β± π
2
Interesting Note:
The difference between the distances from each focus to a point on the curve is
constant. |π1 β π2| = π
Left-Right Opening Hyperbola: π₯(π‘) = π π ππ( π‘) + β π¦(π‘) = π π‘ππ( π‘) + π
[π‘πππ, π‘πππ₯] = [βπ, π] (h, k) = vertex of hyperbola
Up-Down Opening Hyperbola: π₯(π‘) = π π‘ππ(π‘) + β π¦(π‘) = π π ππ(π‘) + π
[π‘πππ, π‘πππ₯] = [βπ, π] (h, k) = vertex of hyperbola
General Form: π₯(π‘) = π΄π‘2 + π΅π‘ + πΆ π¦(π‘) = π·π‘2 + πΈπ‘ + πΉ
where A and D have different signs
Inverse Functions
π(πβ1 (π₯)) = πβ1 (π(π₯)) = π₯
Inverse Function Theorem:
πβ1(π) = 1
πβ²(π)
where π = πβ²(π)
if π¦ = π ππ π ππ π¦ = πππ π ππ π¦ = π‘ππ π
if π¦ = ππ π π if π¦ = π ππ π ππ π¦ = πππ‘ π
π‘βππ π = π ππβ1 π¦ π‘βππ π = πππ β1 π¦ π‘βππ π = π‘ππβ1 π¦
π‘βππ π = ππ πβ1 π¦ π‘βππ π = π ππβ1 π¦ π‘βππ π = πππ‘β1 π¦
π = arcsin π¦ π = arccos π¦ π = ππππ‘ππ π¦ π = πππππ π π¦ π = ππππ ππ π¦ π = ππππππ‘ π¦
Rectangular Polar Parametric .
Copyright Β© 2011-2017 by Harold Toomey, WyzAnt Tutor 7
Arc Length
Circle: πΏ = π = ππ
Proof:
πΏ = (πππππ‘πππ ππ πππππ’ππππππππ) β π β (ππππππ‘ππ)
πΏ = (π
2π) π (2π) = ππ
Perimeter Square: P = 4s
Rectangle: P = 2l + 2w Triangle: P = a + b + c
Circle: C = Οd = 2Οr Ellipse: πΆ β π(π + π)
Area
Square: A = sΒ² Rectangle: A = lw
Rhombus: A = Β½ ab Parallelogram: A = bh
Trapezoid: π΄ =(π1+π2)
2 β
Kite: π΄ = π1 π2
2
Triangle: A = Β½ bh Triangle: A = Β½ ab sin(C)
Triangle: π΄ = βπ (π β π)(π β π)(π β π),
π€βπππ π =π+π+π
2
Equilateral Triangle: π΄ = ΒΌβ3π 2
Frustum: π΄ =1
3(
π1+π2
2) β
Circle: A = ΟrΒ²
Circular Sector: A = Β½ rΒ²π Ellipse: A = Οab
Lateral Surface
Area
Cylinder: S = 2Οrh Cone: S = Οrl
Total Surface
Area
Cube: S = 6sΒ² Rectangular Box: S = 2lw + 2wh + 2hl
Regular Tetrahedron: S = 2bh Cylinder: S = 2Οr (r + h)
Cone: S = ΟrΒ² + Οrl = Οr (r + l)
Sphere: S = 4ΟrΒ² Ellipsoid: S = (too complex)
Volume
Cube: V = sΒ³ Rectangular Prism: V = lwh
Cylinder: V = ΟrΒ²h Triangular Prism: V= Bh
Tetrahedron: V= β bh Pyramid: V = β Bh
Cone: V = β bh = β ΟrΒ²h
Sphere: π =4
3ππ3
Ellipsoid: V = 4
3 Οabc