Intermediate Geometry : Intermediate Geometry

Study concepts, example questions & explanations for Intermediate Geometry

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Example Questions

Example Question #2 : How To Find The Equation Of A Tangent Line

Find the equation for the tangent line at for the circle .

Possible Answers:

Correct answer:

Explanation:

The circle's center is . The tangent line will be perpendicular to the line going through the points  and , so it will be helpful to know the slope of this line:

Since the tangent line is perpendicular, its slope is 

To write the equation in the form , we need to solve for "b," the y-intercept. We can plug in the slope for "m" and the coordinates of the point  for x and y:

The equation is 

Example Question #2 : How To Find The Equation Of A Tangent Line

Find the equation for the tangent line of the circle  at the point .

Possible Answers:

Correct answer:

Explanation:

The circle's center is . The tangent line will be perpendicular to the line going through the points  and , so it will be helpful to know the slope of this line:

Since the tangent line is perpendicular, its slope is .

To write the equation in the form , we need to solve for "b," the y-intercept. We can plug in the slope for "m" and the coordinates of the point  for x and y:

The equation is 

Example Question #3 : How To Find The Equation Of A Tangent Line

Find the equation for the tangent line to the circle at the point .

Possible Answers:

Correct answer:

Explanation:

The circle's center is . The tangent line will be perpendicular to the line going through the points  and , so it will be helpful to know the slope of this line:

Since the tangent line is perpendicular, its slope is 

To write the equation in the form , we need to solve for "b," the y-intercept. We can plug in the slope for "m" and the coordinates of the point  for x and y:

The equation is 

Example Question #8 : How To Find The Equation Of A Tangent Line

Circle

Refer to the above diagram, 

Give the equation of the line tangent to the circle at the point shown.

Possible Answers:

None of the other choices gives the correct response.

Correct answer:

Explanation:

The tangent to a circle at a given point is perpendicular to the radius that has the center and the given point as its endpoints.

The circle has its center at origin ; since this and  are the endpoints of the radius - and the line that includes this radius includes both points - its slope can be found by setting  in the following slope formula:

The tangent line, being perpendicular to this radius, has as its slope the opposite of the reciprocal of this, which is . Since the tangent line includes point , set  in the point-slope formula and simplify:

Example Question #1 : How To Find The Equation Of A Tangent Line

A line is tangent to the circle  at the point 

What is the equation of this line?

Possible Answers:

None of the other answers are correct.

Correct answer:

Explanation:

The center of this circle is 

Therefore, the radius with endpoint  has slope  

The tangent line at  is perpendicular to this radius; therefore, its slope is the opposite of the reciprocal of , or 

Now use the point-slope formula with this slope and the point of tangency:

Example Question #1 : How To Find The Slope Of A Tangent Line

What is the slope of the tangent line to the graph of  when ?

Possible Answers:

Correct answer:

Explanation:

To find the slope of the tangent line, first we must take the derivative of , giving us . Next we simply plug in our given x-value, which in this case is . This leaves us with a slope of .

Example Question #1501 : Intermediate Geometry

Suppose the equation of a line is .  What is the slope of the tangent line at ?

Possible Answers:

Correct answer:

Explanation:

Rewrite  in slope-intercept form, .

The slope of the tangent line is .

 

 

Example Question #1502 : Intermediate Geometry

Suppose a function .  What is the slope of the tangent line at ?

Possible Answers:

Correct answer:

Explanation:

Write the formula for slope-intercept form.

The slope of  is always zero at every point on the domain.  Therefore, the slope at  must also be zero.

Example Question #1 : How To Find X Or Y Intercept

Given the line what is the sum of the and intercepts?

Possible Answers:

Correct answer:

Explanation:

The intercepts cross an axis. 

For the intercept, set to get

For the intercept, set to get

So the sum of the intercepts is .

Example Question #3 : X And Y Intercept

What are the  and -intercepts of the line defined by the equation:

Possible Answers:

Correct answer:

Explanation:

To find the intercepts of a line, we must set the  and  values equal to zero and then solve.  

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