All Precalculus Resources
Example Questions
Example Question #5 : Find The Equation Of A Line Tangent To A Curve At A Given Point
Write the equation for the tangent line to at .
First, find the slope of this tangent line by taking the derivative:
Plugging in 1 for x:
So the slope is 4
Now we need to find the y-coordinate when x is 1, so plug 1 in to the original equation:
To write the equation, use point-slope form and then use algebra to change to slope-intercept like the answer choices:
distribute the 4
add 2 to both sides
Example Question #2 : Find The Equation Of A Line Tangent To A Curve At A Given Point
Write the equation for the tangent line to at .
First, find the slope of the tangent line by taking the first derivative:
To finish determining the slope, plug in the x-value, 2:
the slope is 6
Now find the y-coordinate where x is 2 by plugging in 2 to the original equation:
To write the equation, start in point-slope form and then use algebra to get it into slope-intercept like the answer choices.
distribute the 6
add 8 to both sides
Example Question #1 : Find The Equation Of A Line Tangent To A Curve At A Given Point
Write the equation for the tangent line for at .
First, take the first derivative in order to find the slope:
To continue finding the slope, plug in the x-value, -2:
Then find the y-coordinate by plugging -2 into the original equation:
The y-coordinate is
Now write the equation in point-slope form then algebraically manipulate it to match one of the slope-intercept forms of the answer choices.
distribute the -5
add to both sides
Example Question #1 : Find The Equation Of A Line Tangent To A Curve At A Given Point
Write the equation for the tangent line to at .
First distribute the . That will make it easier to take the derivative:
Now take the derivative of the equation:
To find the slope, plug in the x-value -3:
To find the y-coordinate of the point, plug in the x-value into the original equation:
Now write the equation in point-slope, then use algebra to get it into slope-intercept like the answer choices:
distribute
subtract from both sides
write as a mixed number
Example Question #1 : Limits
Evaluate the limit below:
1
0
will approach when approaches , so will be of type as shown below:
So, we can apply the L’ Hospital's Rule:
since:
hence:
Example Question #21 : Introductory Calculus
Find the limit
When x=3/2 our denominator is zero so we can't just plug in 3/2 to get our limit. If we look at the numerator when x=3/2 we find that it is zero as well so our numerator can be factored. We see that our limit can be re-written as:
we then can cancel the 2x-3 from the numerator and denominator leaving us with:
and we can just plug in 3/2 into this limit to get
note: our function is not continuous at x=3/2 but the limit does exist.
Example Question #22 : Introductory Calculus
Solve the following limit:
To solve this problem we need to expand the term in the numerator
when we do that we get
the second degree x terms cancel and we get
now we can cancel our h's in the numerator and denominator to get
then we can just plug 0 in for h and we get our answer
Example Question #1 : Find The Limit Of A Function
Evaluate the following limit.
The function has a removable discontinuity at . Once a factor of is "divided out" the resultant function is , which evaluates to as approaches 0.
Example Question #11 : Limits
Let .
Find .
The limit does not exist.
This is a graph of . We know that is undefined; therefore, there is no value for . But as we take a look at the graph, we can see that as approaches 0 from the left, approaches negative infinity.
This can be illustrated by thinking of small negative numbers.
NOTE: Pay attention to one-sided limit specifications, as it is easy to pick the wrong answer choice if you're not careful.
is actually infinity, not negative infinity.
Example Question #3 : Limits
Calculate .
The limit does not exist.
This can be rewritten as follows:
We can substitute , noting that as , :
, which is the correct choice.
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