Sponsor Area

Continuity And Differentiability

Question
CBSEENMA12034671

Examine the derivability of the following function:
straight f left parenthesis straight x right parenthesis equals open curly brackets table attributes columnalign left end attributes row cell 3 minus 2 straight x comma space straight x less than 2 end cell row cell 3 straight x minus 7 comma space straight x greater or equal than 2 end cell end table close
at space straight x equals 2

Solution
Here space straight f left parenthesis straight x right parenthesis equals open curly brackets table attributes columnalign left end attributes row cell 3 minus 2 straight x comma space straight x less than 2 end cell row cell 3 straight x minus 7 comma space straight x greater or equal than 2 end cell end table close
straight L. straight H. straight D equals Lt with straight x rightwards arrow 2 to the power of minus below fraction numerator straight f left parenthesis straight x right parenthesis minus straight f left parenthesis 2 right parenthesis over denominator straight x minus 2 end fraction equals Lt with straight x rightwards arrow 2 to the power of minus below space fraction numerator left parenthesis 3 minus 2 straight x right parenthesis minus left parenthesis 6 minus 7 right parenthesis over denominator straight x minus 2 end fraction equals Lt with straight x rightwards arrow 2 to the power of minus below fraction numerator 4 minus 2 straight x over denominator straight x minus 2 end fraction
space space space space space space space space space space space equals Lt with straight x rightwards arrow 2 to the power of minus below fraction numerator negative 2 left parenthesis straight x minus 2 right parenthesis over denominator straight x minus 2 end fraction equals negative 2 Lt with straight x rightwards arrow 2 to the power of minus below left parenthesis 1 right parenthesis equals left parenthesis negative 2 right parenthesis left parenthesis 1 right parenthesis equals negative 2
straight R. straight H. straight D equals Lt with straight x rightwards arrow 2 plus below fraction numerator straight f left parenthesis straight x right parenthesis minus straight f left parenthesis 2 right parenthesis over denominator straight x minus 2 end fraction equals Lt with straight x rightwards arrow 2 to the power of plus below space fraction numerator left parenthesis 3 straight x minus 7 right parenthesis minus left parenthesis 6 minus 7 right parenthesis over denominator straight x minus 2 end fraction equals Lt with straight x rightwards arrow 2 to the power of plus below fraction numerator 3 straight x minus 6 over denominator straight x minus 2 end fraction
space space space space space space space space space space space stack equals Lt with straight x rightwards arrow 2 to the power of plus below fraction numerator 3 left parenthesis straight x minus 2 right parenthesis over denominator straight x minus 2 end fraction equals 3 Lt with straight x rightwards arrow 2 to the power of plus below left parenthesis 1 right parenthesis equals 3 cross times 1 equals 3
therefore space straight L. straight H. straight D not equal to straight R. straight H. straight D.
therefore space straight f left parenthesis straight x right parenthesis space is space not space derivable space at space straight x equals 2.

Some More Questions From Continuity and Differentiability Chapter