Calculus 1 : Graphing Functions

Study concepts, example questions & explanations for Calculus 1

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Example Questions

Example Question #11 : Lines

Find the slope of the tangent line  to the following function at .

Possible Answers:

None of these

Correct answer:

Explanation:

To find the slope of the line tangent to the function at a point you must first find the derivative.

The power rule states that the derivative of  is .

The derivative of  is .

The derivative of the function is

.

Plugging in 1 for x gives 

.

Example Question #2711 : Calculus

Given the differential function , we are told that , , and .  Which of the following must be true?

Possible Answers:

The line is tangent to .

must have at least one relative maximum.

has a point of inflection at .

is increasing over the interval .

is decreasing at .

Correct answer:

The line is tangent to .

Explanation:

" is decreasing at ." is incorrect.  The function is increasing at because .

" is increasing over the interval ." is possibly true, but there is not enough information to conclude that it must be true.

" has a point of inflection at ." is possibly true.  Although we know that , a requirement for an inflection point, we do not know that changes signs at .

" must have at least one relative maximum." is possibly true, but there is not enough information to conclude that it must be true.

"The line is tangent to ." must be true.  Because , the function travels through the point .  Because , the slope of the line tangent to the curve at is 5.  Use point-slope form to determine the equation of the tangent line.

Example Question #242 : Graphing Functions

Find the equation for the line tangent to the curve  at .

Possible Answers:

Correct answer:

Explanation:

The derivative of the function is , and is found using the power rule

 

and the rule for the derivative of natural log which is, 

 

so plugging in  gives , which must be the slope of the line since the tangent line's slope is determined by the derivative.

Thus, the line is of the form , where b is unknown.

Solve for b by setting the equation equal to  and plugging in  for x since that is the given point. 

, which gives us 

Example Question #11 : How To Find Equation Of Line By Graphing Functions

Find the slope of the tangent line through the given point of the following function.

 at the point 

Possible Answers:

Correct answer:

Explanation:

In order to find the slope of the tangent line through a certain point, we must find the rate of change (derivative) of the function.  The derivative of   is written as .  This tells us what the slope of the tangent line is through any point  in our function .  In other words, all we need to do is plug-in  (because our point  has an x-value of 1) into .  This will give us our answer,  .

Example Question #17 : Equation Of Line

Find the tangent line to the function  at the point .

Possible Answers:

Correct answer:

Explanation:

To find the tangent line one must first find the slope, this can be given by the derivative evaluated at a point.

To find the derivative of this function use the power rule which states,

The derviative of  is .

Evaluated at our point ,

we find that the slope, m is also 3.

Now we may use the point-slope equation of a line to find the tangent line.

The point slope equation is 

 Where  is the point at which the line is tangent.

Using this definition we find the tangent line to be defined by .

 

Example Question #1 : How To Find Slope By Graphing Functions

What is the slope of the tangent line of f(x) = 3x4 – 5x3 – 4x at x = 40?

Possible Answers:

684,910

768,000

331,841

743,996

None of the other answers

Correct answer:

743,996

Explanation:

The first derivative is easy:

f'(x) = 12x3 – 15x2 – 4

The slope of the tangent line is found by calculating f'(40) = 12 * 403 – 15 * 402 – 4 = 768,000 – 24,000 – 4 = 743,996

Example Question #241 : Graphing Functions

Find the slope of the line tangent to  when  is equal to .

Possible Answers:

Correct answer:

Explanation:

To find the slope of a tangent line, we need to find the first derivative of the function at that point. In other words, we need y'(6).

Taking the first derivative using the Power Rule  we get the following.

Substituting in 6 for b and solving we get:

.

So our answer is 320160

Example Question #242 : Graphing Functions

Find function which gives the slope of the line tangent to .

Possible Answers:

Correct answer:

Explanation:

To find the slope of a tangent line, we need the first derivative.

Recall that to find the first derivative of a polynomial, we need to decrease each exponent by one and multiply by the original number.

Example Question #2 : How To Find Slope By Graphing Functions

Find the slope of the line tangent to  at .

Possible Answers:

Correct answer:

Explanation:

The slope of the tangent line can be found easily via derivatives. To find the slope of the tangent line at s=16, find b'(16) using the power rule on each term which states:

Applying this rule we get:

Therefore, the slope we are looking for is 454.

 

Example Question #3 : How To Find Slope By Graphing Functions

Find the slope of  at .

Possible Answers:

Correct answer:

Explanation:

To find the slope of the line at that point, find the derivative of f(x) and plug in that point. 

Remember that the derivative of  and the derivative of   

Now plug in  

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