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If #f(x)=x^2-x#, how do you find #f(2x)#?

Answer 1

Theodore Amidon

#4x^2-2x#

All that is required here is to substitute x = 2x into the right side in the same way that is done for a numeric value.

#f(x)=x^2-x#

f(2) means substitute x = 2

#rArrf(2)=2^2-2=4-2=2#

In the same way:

#f(2x)=(2x)^2-(2x)=4x^2-2x#

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Answer 2

Theodore Amidon

To find ( f(2x) ) when ( f(x) = x^2 - x ), substitute ( 2x ) for ( x ) in the expression for ( f(x) ).

So, ( f(2x) = (2x)^2 - (2x) ).

This simplifies to ( f(2x) = 4x^2 - 2x ).

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.