Problemas
For f(x)=3x^2+9x+8 find the equation of the tangent line at the following values of x. (a) x=1 The equation of the tangent line at x=1 is square (b) x=-1 The equation of the tangent line at x=-1 is square
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David
experto · Tutor durante 3 años
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(199 Votos)
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To find the equation of the tangent line to the function
at a given value of
, we need to find the derivative of the function and then evaluate it at the given value of
to find the slope of the tangent line. Finally, we can use the point-slope form of a linear equation to find the equation of the tangent line.Let's start with part (a) where
.Step 1: Find the derivative of the function
.The derivative of
is given by:
Step 2: Evaluate the derivative at
to find the slope of the tangent line.
Step 3: Use the point-slope form of a linear equation to find the equation of the tangent line.The point-slope form of a linear equation is given by:
where
is the slope of the line and
is a point on the line.In this case, the slope of the tangent line is
, and we can choose the point
on the line. So, the equation of the tangent line at
is:
Step 4: Substitute the value of
into the equation.
So, the equation of the tangent line at
is:
Simplifying the equation, we get:
Therefore, the equation of the tangent line at
is
.Now let's move on to part (b) where
.Step 1: Find the derivative of the function
.The derivative of
is given by:
Step 2: Evaluate the derivative at
to find the slope of the tangent line.
Step 3: Use the point-slope form of a linear equation to find the equation of the tangent line.The point-slope form of a linear equation is given by:
where
is the slope of the line and
is a point on the line.In this case, the slope of the tangent line is
, and we can choose the point
on the line. So, the equation of the tangent line at
is:
Step 4: Substitute the value of
into the equation.
So, the equation of the tangent line at
is:
Simplifying the equation, we get:
Therefore, the equation of the tangent line at
is
.