values for constants making piecewise fcn continuous  TOPIC_SOLVED

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values for constants making piecewise fcn continuous

Postby nona.m.nona on Wed Mar 18, 2009 3:03 pm

I have the following function:



I need to find the values of "a", "b", and "c" that will make this function continuous.

I thought the limit on the third part, as x goes to 0, could be found using the limit from back when we were doing trig derivatives. But using "sin(theta)/theta, as theta goes to 0" won't work, because if theta = 1/x, then theta is actually going to infinity.

On the other hand, 0< 2 + xsin(1/x)<2 + x, since 0<sin(theta)<1 for x "close to" 0. I'm taking this to mean that the limit at 0 is 0, so c = 0.

Then ax + b has to equal 0 at x = 0, so b = 0. But I can't figure out the answer for a.
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Postby stapel_eliz on Thu Mar 19, 2009 2:54 pm

nona.m.nona wrote:But I can't figure out the answer for a.

I believe the answer will be that any value for will be acceptable. It's only the y-intercept that must be a particular value in order for the "ends" to meet at x = 0.

The slope of the straight line, as it approaches from the left, is irrelevant. :wink:
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Re: values for constants making piecewise fcn continuous

Postby nona.m.nona on Sat Mar 21, 2009 1:21 pm

stapel_eliz wrote:
nona.m.nona wrote:But I can't figure out the answer for a.

I believe the answer will be that any value for will be acceptable.

I didn't know I could do that. Thanks! :thumb:
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