Is this the same as lim x→2 sin(x)?

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SUMMARY

The limit evaluation lim h→0 (f(2+h)-f(2))/h for the function f(x)=sin(x) is not equivalent to sin(2). The correct approach involves applying the definition of the derivative, which leads to the conclusion that the limit evaluates to cos(2). Numerical evaluation using small values of h, such as 1/2, 1/4, and 1/8, can provide insight into the behavior of the function near x=2, confirming that the limit approaches cos(2) rather than sin(2).

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Homework Statement


if f(x)=sin(x), evaluate lim h→0 (f(2+h)-f(2))/h) to two decimal places

Homework Equations


(f(x+h)-f(x))/h

The Attempt at a Solution


On the assumption that this is the same as lim x→2 sin(x)
sin(2)=0.91
 
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AllanW said:

Homework Statement


if f(x)=sin(x), evaluate lim h→0 (f(2+h)-f(2))/h) to two decimal places

Homework Equations


(f(x+h)-f(x))/h

The Attempt at a Solution


On the assumption that this is the same as lim x→2 sin(x)
sin(2)=0.91
No, the limit at the top is not the same as sin(2).
 
AllanW said:

Homework Statement


if f(x)=sin(x), evaluate lim h→0 (f(2+h)-f(2))/h) to two decimal places

Homework Equations


(f(x+h)-f(x))/h

The Attempt at a Solution


On the assumption that this is the same as lim x→2 sin(x)
sin(2)=0.91

Instead of "guessing" and remaining uncertain, try evaluating ##(f(2+h)-f(2))/h## numerically for a few small values of ##h##, such as ##h = 1/2,\, 1/4,\, 1/8, \ldots, ## etc. That way, you can answer your question for yourself and you will furthermore understand much better what is happening.
 
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