MATH TRICKS : ONE-ONE OR INJECTIVE FUNCTION FIND IN JUST TWO SEC FOR JEE MAIN/IIT JEE/CBSE/WBJEE/BITSAT/NDA/CLASS 12TH
– A function is said to be an one-one or injective function , if that the function is strictly increasing .
a function f(x) , now f(x) is said to be an one-one if derivative of that function greater or equal zero(0) .
Ex. Check whether f (x) =x3 is one-one function or not ?
Given , f(x) = x3 , now taking derivative w.r.t x
f‘ (x) = 3x2 ≥ 0 ∀ x ∈R then f (x) is strictly increasing function hence f(x) is one-one function .
Q . Check whether f (x) is one-one function or not ?
(i) f(x) = x+sinx
(ii) f(x) = x3 +x2 + 4x + 4
(iii) f (x) = ex
This is the very simple method to find one-one or injective function for wbjee math tricks , jee main math tricks , jee advanced math tricks ……
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