Precalculus : Hyperbolas and Ellipses

Study concepts, example questions & explanations for Precalculus

varsity tutors app store varsity tutors android store

Example Questions

Example Question #131 : Conic Sections

Find the endpoints of the major axis for the ellipse with the following equation:

\displaystyle \frac{x^2}{64}+\frac{y^2}{49}=1

Possible Answers:

\displaystyle (8,0)(0,8)

\displaystyle (0,0)(0,8)

\displaystyle (0, 8)(0, -8)

\displaystyle (8, 0)(-8, 0)

Correct answer:

\displaystyle (8, 0)(-8, 0)

Explanation:

Recall the standard form of the equation of an ellipse:

\displaystyle \frac{(x-h)^2}{a^2}+\frac{(y-k)^2}{b^2}=1, where \displaystyle (h,k) is the center of the ellipse.

When \displaystyle a>b, the major axis is horizontal. In this case, \displaystyle (h-a, k) and \displaystyle (h+a, k) are the endpoints of the major axis.

When \displaystyle b>a\displaystyle (h, k+b) and \displaystyle (h, k-b) are the endpoints of the major axis.

 

For the ellipse in question, \displaystyle (0,0) is the center. In addition, \displaystyle a=8 and \displaystyle b=7. Since \displaystyle a>b, the major axis is horizontal and the endpoints are \displaystyle (8, 0) and \displaystyle (-8, 0)

Example Question #41 : Hyperbolas And Ellipses

Find the endpoints of the major axis for the ellipse with the following equation:

\displaystyle \frac{x^2}{100}+\frac{y^2}{400}=1

Possible Answers:

\displaystyle (20, 0)(-20, 0)

\displaystyle (10, 0)(20, 0)

\displaystyle (10, 0)(-10, 0)

\displaystyle (0, 20)(0, -20)

Correct answer:

\displaystyle (0, 20)(0, -20)

Explanation:

Recall the standard form of the equation of an ellipse:

\displaystyle \frac{(x-h)^2}{a^2}+\frac{(y-k)^2}{b^2}=1, where \displaystyle (h,k) is the center of the ellipse.

When \displaystyle a>b, the major axis is horizontal. In this case, \displaystyle (h-a, k) and \displaystyle (h+a, k) are the endpoints of the major axis.

When \displaystyle b>a\displaystyle (h, k+b) and \displaystyle (h, k-b) are the endpoints of the major axis.

 

For the ellipse in question, \displaystyle (0,0) is the center. In addition, \displaystyle a=10 and \displaystyle b=20. Since \displaystyle b>a, the major axis is vertical and the endpoints are \displaystyle (0, 20) and \displaystyle (0, -20).

Example Question #1712 : Pre Calculus

Find the endpoints of the major axis of the ellipse with the following equation:

\displaystyle \frac{(x-2)^2}{225}+\frac{(y+11)^2}{256}=1

Possible Answers:

\displaystyle (2, -27)(2,5)

\displaystyle (-27, 2)(5, 2)

\displaystyle (17, 2)(-11, 13)

\displaystyle (17, -11)(-13, -11)

Correct answer:

\displaystyle (2, -27)(2,5)

Explanation:

Recall the standard form of the equation of an ellipse:

\displaystyle \frac{(x-h)^2}{a^2}+\frac{(y-k)^2}{b^2}=1, where \displaystyle (h,k) is the center of the ellipse.

When \displaystyle a>b, the major axis is horizontal. In this case, \displaystyle (h-a, k) and \displaystyle (h+a, k) are the endpoints of the major axis.

When \displaystyle b>a\displaystyle (h, k+b) and \displaystyle (h, k-b) are the endpoints of the major axis.

 

For the ellipse in question, \displaystyle (2,-11) is the center. In addition, \displaystyle a=15 and \displaystyle b=16. Since \displaystyle b>a, the major axis is vertical and the endpoints are \displaystyle (2, -27) and \displaystyle (2, 5).

Example Question #44 : Hyperbolas And Ellipses

Find the endpoints of the major axis of the ellipse with the following equation:

\displaystyle \frac{(x+5)^2}{169}+\frac{(y-3)^2}{144}=1

Possible Answers:

\displaystyle (8, 3)(-18, 3)

\displaystyle (-5, 15)(3, -18)

\displaystyle (-5, 15)(-5, -9)

\displaystyle (3, 8)(-18, 3)

Correct answer:

\displaystyle (8, 3)(-18, 3)

Explanation:

Recall the standard form of the equation of an ellipse:

\displaystyle \frac{(x-h)^2}{a^2}+\frac{(y-k)^2}{b^2}=1, where \displaystyle (h,k) is the center of the ellipse.

When \displaystyle a>b, the major axis is horizontal. In this case, \displaystyle (h-a, k) and \displaystyle (h+a, k) are the endpoints of the major axis.

When \displaystyle b>a\displaystyle (h, k+b) and \displaystyle (h, k-b) are the endpoints of the major axis.

 

For the ellipse in question, \displaystyle (-5, 3) is the center. In addition, \displaystyle a=13 and \displaystyle b=12. Since \displaystyle a>b, the major axis is horizontal and the endpoints are \displaystyle (8, 3) and \displaystyle (-18, 3)

Example Question #45 : Hyperbolas And Ellipses

Find the endpoints of the major axis of the ellipse with the following equation:

\displaystyle 25x^2+49y^2+200x-294y-284=0

Possible Answers:

\displaystyle (4, 8)(4, -2)

\displaystyle (3, 11)(3, -3)

\displaystyle (11, 3)(-3, 3)

\displaystyle (3, 11)(4, 8)

Correct answer:

\displaystyle (11, 3)(-3, 3)

Explanation:

Recall the standard form of the equation of an ellipse:

\displaystyle \frac{(x-h)^2}{a^2}+\frac{(y-k)^2}{b^2}=1, where \displaystyle (h,k) is the center of the ellipse.

Start by putting the equation in the standard form as shown above.

Group the \displaystyle x terms and \displaystyle y terms together.

\displaystyle 25x^2+49y^2+200x-294y-284=0

\displaystyle 25x^2+200x+49y^2-294y-284=0

Factor out \displaystyle 25 from the \displaystyle x terms and \displaystyle 49 from the \displaystyle y terms.

\displaystyle 25(x^2-8x)+49(y^2-6y)-284=0

Now, complete the squares. Remember to add the same amount to both sides of the equation!

\displaystyle 25(x^2-8x+16)+49(y^2-6y+9)-284=841

Add \displaystyle 284 to both sides.

\displaystyle 25(x^2-8x+16)+49(y^2-6y+9)=1125

Divide by \displaystyle 1125 on both sides.

\displaystyle \frac{x^2-8x+16}{49}+\frac{y^2-6y+9}{25}=1

Now factor both terms to get the standard form of the equation of an ellipse.

\displaystyle \frac{(x-4)^2}{49}+\frac{(y-3)^2}{25}=1

Recall that when \displaystyle a>b, the major axis is horizontal. In this case, \displaystyle (h-a, k) and \displaystyle (h+a, k) are the endpoints of the major axis.

When \displaystyle b>a\displaystyle (h, k+b) and \displaystyle (h, k-b) are the endpoints of the major axis.

For the ellipse in question, \displaystyle (4, 3) is the center. In addition, \displaystyle a=7 and \displaystyle b=5. Since \displaystyle a>b, the major axis is horizontal and the endpoints are \displaystyle (11, 3) and \displaystyle (-3, 3).

Example Question #46 : Hyperbolas And Ellipses

Find the endpoints of the major axis of the ellipse with the following equation:

\displaystyle 9x^2+18y^2-108x-360y+1962=0

Possible Answers:

\displaystyle (6, 13)(6, 7)

\displaystyle (6, 10+3\sqrt2)(6, 10-3\sqrt2)

\displaystyle (6+3\sqrt2, 10)(6-3\sqrt2, 10)

\displaystyle (3\sqrt2, 6)(-3\sqrt2, 6)

Correct answer:

\displaystyle (6+3\sqrt2, 10)(6-3\sqrt2, 10)

Explanation:

Recall the standard form of the equation of an ellipse:

\displaystyle \frac{(x-h)^2}{a^2}+\frac{(y-k)^2}{b^2}=1, where \displaystyle (h,k) is the center of the ellipse.

Start by putting the equation in the standard form as shown above.

Group the \displaystyle x terms and \displaystyle y terms together.

\displaystyle 9x^2+18y^2-108x-360y+1962=0

\displaystyle 9x^2-108x+18y^2-360y+1962=0

Factor out \displaystyle 9 from the \displaystyle x terms and \displaystyle 18 from the \displaystyle y terms.

\displaystyle 9(x^2-12x)+18(y^2-20y)+1962=0

Now, complete the squares. Remember to add the same amount to both sides of the equation!

\displaystyle 9(x^2-12x+36)+18(y^2-20y+100)+1962=2124

Subtract \displaystyle 1962 from both sides.

\displaystyle 9(x^2-12x+36)+18(y^2-20y+100)=162

Divide by \displaystyle 162 on both sides.

\displaystyle \frac{x^2-12x+36}{18}+\frac{y^2-20x+100}{9}=1

Now factor both terms to get the standard form of the equation of an ellipse.

\displaystyle \frac{(x-6)^2}{18}+\frac{(y-10)^2}{9}=1

Recall that when \displaystyle a>b, the major axis is horizontal. In this case, \displaystyle (h-a, k) and \displaystyle (h+a, k) are the endpoints of the major axis.

When \displaystyle b>a\displaystyle (h, k+b) and \displaystyle (h, k-b) are the endpoints of the major axis.

For the ellipse in question, \displaystyle (6, 10) is the center. In addition, \displaystyle a=\sqrt{18}=3\sqrt2 and \displaystyle b=3. Since \displaystyle a>b, the major axis is horizontal and the endpoints are \displaystyle (6+3\sqrt2, 10) and \displaystyle (6-3\sqrt2, 10).

Example Question #42 : Understand Features Of Hyperbolas And Ellipses

Find the endpoints of the minor axis of the ellipse with the following equation:

\displaystyle \frac{x^2}{100}+\frac{y^2}{169}=1

Possible Answers:

\displaystyle (0, 13)(0, -13)

\displaystyle (10, 0)(-10, 0)

\displaystyle (0, 10)(0, -10)

\displaystyle (13, 10)(-13, 10)

Correct answer:

\displaystyle (10, 0)(-10, 0)

Explanation:

Recall the standard form of the equation of an ellipse:

\displaystyle \frac{(x-h)^2}{a^2}+\frac{(y-k)^2}{b^2}=1, where \displaystyle (h,k) is the center of the ellipse.

When \displaystyle a< b, the minor axis is horizontal. In this case, \displaystyle (h-a, k) and \displaystyle (h+a, k) are the endpoints of the minor axis.

When \displaystyle b< a\displaystyle (h, k+b) and \displaystyle (h, k-b) are the endpoints of the vertical minor axis.

 

For the ellipse in question, \displaystyle (0,0) is the center. In addition, \displaystyle a=10 and \displaystyle b=13. Since \displaystyle a< b, the minor axis is horizontal and the endpoints are \displaystyle (10, 0) and \displaystyle (-10, 0)

Example Question #48 : Hyperbolas And Ellipses

Find the endpoints of the minor axis of the ellipse with the following equation:

\displaystyle \frac{x^2}{225}+\frac{y^2}{400}=1

Possible Answers:

\displaystyle (15, 20)(-15, 20)

\displaystyle (0, 20)(0, -20)

\displaystyle (15, 0)(-15, 0)

\displaystyle (0, 15)(0, -15)

Correct answer:

\displaystyle (15, 0)(-15, 0)

Explanation:

Recall the standard form of the equation of an ellipse:

\displaystyle \frac{(x-h)^2}{a^2}+\frac{(y-k)^2}{b^2}=1, where \displaystyle (h,k) is the center of the ellipse.

When \displaystyle a< b, the minor axis is horizontal. In this case, \displaystyle (h-a, k) and \displaystyle (h+a, k) are the endpoints of the minor axis.

When \displaystyle b< a\displaystyle (h, k+b) and \displaystyle (h, k-b) are the endpoints of the vertical minor axis.

 

For the ellipse in question, \displaystyle (0,0) is the center. In addition, \displaystyle a=15 and \displaystyle b=20. Since \displaystyle a< b, the minor axis is horizontal and the endpoints are \displaystyle (15, 0) and \displaystyle (-15, 0)

Example Question #49 : Hyperbolas And Ellipses

Find the endpoints of the minor axis of the ellipse with the following equation:

\displaystyle \frac{(x-5)^2}{25}+\frac{(y-1)^2}{36}=1

Possible Answers:

\displaystyle (0, 1)(10, 1)

\displaystyle (1, 5)(10, 5)

\displaystyle (1, 0)(10, 1)

\displaystyle (5, 7)(5, -5)

Correct answer:

\displaystyle (0, 1)(10, 1)

Explanation:

Recall the standard form of the equation of an ellipse:

\displaystyle \frac{(x-h)^2}{a^2}+\frac{(y-k)^2}{b^2}=1, where \displaystyle (h,k) is the center of the ellipse.

When \displaystyle a< b, the minor axis is horizontal. In this case, \displaystyle (h-a, k) and \displaystyle (h+a, k) are the endpoints of the minor axis.

When \displaystyle b< a\displaystyle (h, k+b) and \displaystyle (h, k-b) are the endpoints of the vertical minor axis.

 

For the ellipse in question, \displaystyle (5,1) is the center. In addition, \displaystyle a=5 and \displaystyle b=6. Since \displaystyle a< b, the minor axis is horizontal and the endpoints are \displaystyle (0,1) and \displaystyle (10, 1).

Example Question #50 : Hyperbolas And Ellipses

Find the endpoints of the minor axis of the ellipse with the following equation:

\displaystyle 25x^2+20y^2+200x-120y+80=0

Possible Answers:

\displaystyle (-4, 8)(-4, 2\sqrt5)

\displaystyle (-4, 8)(-4, -2)

\displaystyle (3, -4+2\sqrt5)(3, -4-2\sqrt5)

\displaystyle (-4+2\sqrt5, 3)(-4-2\sqrt5, 3)

Correct answer:

\displaystyle (-4+2\sqrt5, 3)(-4-2\sqrt5, 3)

Explanation:

Recall the standard form of the equation of an ellipse:

\displaystyle \frac{(x-h)^2}{a^2}+\frac{(y-k)^2}{b^2}=1, where \displaystyle (h,k) is the center of the ellipse.

Start by putting the equation in the standard form as shown above.

Group the \displaystyle x terms and \displaystyle y terms together.

\displaystyle 25x^2+20y^2+200x-120y+80=0

\displaystyle 25x^2+200x+20y^2-120y+80=0

Factor out \displaystyle 25 from the \displaystyle x terms and \displaystyle 20 from the \displaystyle y terms.

\displaystyle 25(x^2+8x)+20(y^2-6y)+80=0

Now, complete the squares. Remember to add the same amount to both sides of the equation!

\displaystyle 25(x^2+8x+16)+20(y^2-6y+9)+80=580

Subtract \displaystyle 80 from both sides.

\displaystyle 25(x^2+8x+16)+20(y^2-6y+9)=500

Divide by \displaystyle 500 on both sides.

\displaystyle \frac{x^2+8x+16}{20}+\frac{y^2-6x+9}{25}=1

Now factor both terms to get the standard form of the equation of an ellipse.

\displaystyle \frac{(x+4)^2}{20}+\frac{(y-3)^2}{25}=1

When \displaystyle a< b, the minor axis is horizontal. In this case, \displaystyle (h-a, k) and \displaystyle (h+a, k) are the endpoints of the minor axis.

When \displaystyle b< a\displaystyle (h, k+b) and \displaystyle (h, k-b) are the endpoints of the vertical minor axis.

For the ellipse in question, \displaystyle (-4, 3) is the center. In addition, \displaystyle a=\sqrt{20}=2\sqrt5 and \displaystyle b=5. Since \displaystyle a< b, the minor axis is horizontal and the endpoints are \displaystyle (-4+2\sqrt5, 3) and \displaystyle (-4-2\sqrt5, 3).

Learning Tools by Varsity Tutors