Aptitude Questions and Answers
Functions f and g are defined by:
f(x) = 1/x + 3x and g(x) = -1/x + 6x - 4
The domain of (f+g)(x) is:
(f + g)(x) = f(x) + g(x) = (1/x + 3x) + (-1/x + 6x - 4)
(f + g)(x) = 9 x - 4
Domain of f + g is given by the interval (-infinity , 0) U (0 , + infinity)
The range of the function f(x)= x2 - 4x + 9 is:
h(x) = x 2 - 4 x + 9 = x 2 - 4 x + 4 - 4 + 9 = (x - 2) 2 + 5
(x - 2) 2 >= 0
(x - 2) 2 + 5 >= 5
Hence minimum value h(x) can have is 5 and maximum can go upto + infinity. So the range is [5 , + infinity)