Most Important Selected Qs for JEE AdvancedMathematicsApplication of Derivatives
Let f and g be functions from the interval [0, ) to the interval [0, ) f being an increasing function and g being a decreasing function. If f g(0) =0 , then
Options
- Af g(x) f g(0)
- Bg f ( x ) g f (0)
- Cf g(1) =0
- Dnone of these
Correct answer
B. g f ( x ) g f (0)
Step-by-step solution
aligned & 'g' is decreasing & g(1) g(0) & Therefore f is increasing & f g(0) f g(1) & 0 f g(1) , from the question. But, f(x) 0 , from the question & f g(1) =0 aligned aligned & As x 0, ~g ( x ) g (0) & So, f g ( x ) f g (0) & As x 0, f ( x ) f (0) & So, g f ( x ) g f (0) aligned