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Q.
$f : R \rightarrow R$ defined by $f(x) = \cos (2x + 3)$ is
Relations and Functions - Part 2
Solution:
$\cos (2x_1 + 3) = \cos (2x_2 + 3) \Rightarrow x_1 \neq x_2 \Rightarrow $ is not one-one .
Range of f = = [-1,1] $\neq $ codomain $\Rightarrow $ f is not onto