Monday, 14 March 2016

calculus - Determine the value of k, if any, that makes k continuous everywhere for this piece wise function.




Let
h(x)={sin(kx),if x2,x+k2,if x>2,
where k is a real constant. Determine the value of k, if any, that makes k continuous everywhere.




I done my work and here goes.






Since h(x) is continuous on (,2) and on (2,), it suffice to find the value of k such that h(x) is continuous at x=2.



Suppose h(x) is continuous at x=0, then lim
and \lim_{x\to2^+}h(x)=\lim_{x\to2^+}x+k^2=2+k^2
Therefore, \lim_{x\to2^+}h(x)=\lim_{x\to2^-}h(x) implies \sin(2k)=2+k^2






Ok so now I am stuck. Thanks in advance for helping me out!


Answer



Your work so far is fine.



Hint: \sin(-) is always between -1 and 1.


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