更新1:
The problem is Use the limit definition to find the slope of the tangent line to the graph of f at the given point. f(x) = 4; (-5,4) Not having an x in the f(x) is throwing me off in using the difference quotient(???)
Difference quotient math help please?
回答 (3)
2017-08-28 5:05 am
The difference quotient is:
[f(x + h) - f(x)] / h
And then if you take the limit of h as it approaches zero, you get the first derivative of the original function.
So if you have f(x) = 4, then the output of the function regardless of input is 4, so we end up with:
[4 - 4] / h
0 / h
So as h approaches zero, this expression approaches zero.
So the slope of the line at all points is zero.
[f(x + h) - f(x)] / h
And then if you take the limit of h as it approaches zero, you get the first derivative of the original function.
So if you have f(x) = 4, then the output of the function regardless of input is 4, so we end up with:
[4 - 4] / h
0 / h
So as h approaches zero, this expression approaches zero.
So the slope of the line at all points is zero.
2017-08-28 4:59 am
Slope = [4-4]/h = 0
2017-08-28 5:28 am
f(x) = 4 is a constant function, not a number
Its value is 4 no matter what the input to f, so for example f(-5)=4, f(h)=4, f(17)=4, f(-5+h)=4, etc.
So, just use the usual formula for difference quotient.
Its value is 4 no matter what the input to f, so for example f(-5)=4, f(h)=4, f(17)=4, f(-5+h)=4, etc.
So, just use the usual formula for difference quotient.
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