Derivatives, Sin and Cos, Rate of Change, Tangent Lines

JackieAnne
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Hi, I am in calculus and am having major struggles. If someone could provide a walk through on how to answer these questions, that would be fantastic. Cheers!

Let f(x)=−3x+6 if x<-3
= 15 if x > -3

Find the average rate of change of f(x) on the interval −5<x<5 .

The average rate of change of f(x) on the interval −5<x<5 is ?


Consider the function f(x)=−7/x+4.

We will take steps to find the tangent line to the graph of f at the point (−7,−3/−7).

(a) Let (xf(x)) be a point on the graph of f with x=−7 . The slope of the (secant) line joining the two points (−7,−3/−7) and (xf(x)) can be simplified to the form A/x+4, where A is a constant. Find A.

Answer: A= .

(b) By considering the slope of the secant line as x approaches −7, find the slope of the tangent line to the graph of f at the point (−7,−3/−7).

Answer: The slope of the tangent line to the graph of f at the point (−7,−3/−7) is .

(c) Find the equation of the tangent line to the graph of f at the point (−7,−3/−7). Write your answer in the form y=mx+b.
 
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JackieAnne said:
Hi, I am in calculus and am having major struggles. If someone could provide a walk through on how to answer these questions, that would be fantastic. Cheers!

Let f(x)=−3x+6 if x<-3
= 15 if x > -3

Find the average rate of change of f(x) on the interval −5<x<5 .

The average rate of change of f(x) on the interval −5<x<5 is ?


Consider the function f(x)=−7/x+4.

We will take steps to find the tangent line to the graph of f at the point (−7,−3/−7).

(a) Let (xf(x)) be a point on the graph of f with x=−7 . The slope of the (secant) line joining the two points (−7,−3/−7) and (xf(x)) can be simplified to the form A/x+4, where A is a constant. Find A.

Answer: A= .

(b) By considering the slope of the secant line as x approaches −7, find the slope of the tangent line to the graph of f at the point (−7,−3/−7).

Answer: The slope of the tangent line to the graph of f at the point (−7,−3/−7) is .

(c) Find the equation of the tangent line to the graph of f at the point (−7,−3/−7). Write your answer in the form y=mx+b.

What have you tried? Before we can offer help, you must have made an effort on your own behalf.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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