Let f : R → R defined by $f(x)=2 x^3-7$ for $x \in R$. Then : (A) f is one-one function Choose the correct answer from the options given below: |
(A) and (D) only (B) and (D) only (B) and (C) only (A) and (C) only |
(A) and (C) only |
The correct answer is Option (4) - (A) and (C) only for $y=2x^3-7⇒\frac{(y+7)^{\frac{1}{3}}}{2}=x$ for every y atleast some x exists (ONTO function) for $y_1=y_2$ $2x_1^3-7=2x_2^3-7$ so $x_1^3=x_2^3⇒x_1=x_2$ always (ONE ONE) ⇒ it is bijective |