Problems from Computation of images and inverse images

Consider the function $f$ defined by three plus the root of a given real number. Find its analytical expression as well as $f (1), f (4)$ and $f^{- 1} (7)$ .

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Development:

We write the algebraic expression of the function:

$f (x) = \sqrt{x} + 3$

We can calculate now: $f (1) = \sqrt{1} + 3 = 1 + 3 = 4$ $f (4) = \sqrt{4} + 3 = 2 + 3 = 5$ $f^{- 1} (7) :$ $7 = \sqrt{x} + 3$ $4 = \sqrt{x}$ $x = 16$

Solution:

$f (x) = \sqrt{x} + 3$

$f (1) = 4$

$f (4) = 5$

$f^{- 1} (7) = 16$

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