Find the values of a and b so that the function f given by is continuous at x = 3 and x = 5

Given:


f(x) is continuous at x = 3 & x = 5


If f(x) to be continuous at x = 3,then,f(3) = f(3) + = f(3)


LHL = f(3) =


= 1 ...(1)


RHL = f(3) + =



a(3 + 0) + b


3a + b ...(2)


Since ,f(x) is continuous at x = 3 and From (1) & (2),we get


3a + b = 1 ...(3)


Similarly ,f(x) is continuous at x = 5


If f(x) to be continuous at x = 5,then, f(5) = f(5) + = f(5)


LHL = f(5) =



a(5–0) + b


5a + b ...(4)


RHL = f(5) + =


7 ...(5)


Since , f(x) is continuous at x = 5 and From (4) & (5),we get,


5a + b = 7 ...(6)


Now equate (3) & (6)



a = 3


Now Substitute a = 3 in any one of above equation(3) & (6) ,


3a + b = 1


3(3) + b = 1


9 + b = 1


b = –8


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