The local linear approximation of a function f will always be greater than or equal to the function's value if, for all x in an interval containing the point of tangency,

A) f'<0

B) f'>0

C) f''<0

D) f''>0

E) f'=f''=0

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- February 10th 2008, 01:06 PMDINOCALC09local linear approximation
The local linear approximation of a function f will always be greater than or equal to the function's value if, for all x in an interval containing the point of tangency,

A) f'<0

B) f'>0

C) f''<0

D) f''>0

E) f'=f''=0 - February 10th 2008, 02:46 PMwingless
means that the graph is always concave down. Looking at the graph will probably give you an idea why all linear approximations on such function are always larger or equal to the function.

http://img116.imageshack.us/img116/6928/graph2lu7.png - February 10th 2008, 03:16 PMDINOCALC09
so C is the correct the answer?

- February 10th 2008, 03:27 PMwingless
- February 10th 2008, 03:33 PMDINOCALC09
yes, f''(x) is the 2nd derivative

- February 10th 2008, 04:01 PMDINOCALC09
ok the answer is B. thank you