Question

Seja f a função de R em R definida por f(x) = x² - 3x + 4, Calcular:

a) f(1/2)
b) f(-1/3)
c) f(√3)
d) f(1-√2)

Answer 1

f(x) = x² - 3x + 4, Calcular:

a)
f(1/2)=>
$f( \frac{1}{2}) = (\frac{1}{2} ) ^{2} - 3. \frac{1}{2} + 4 = \\ \\ f( \frac{1}{2} ) = \frac{1}{4} - \frac{3}{2} + \frac{4}{1} = \\ \\ f( \frac{1}{2} ) = \frac{1 - 6 + 16}{4} \\ \\ f( \frac{1}{2} ) = \frac{17 - 6}{4} \\ \\ f( \frac{1}{2} ) = \frac{11}{4}$

b) f(-1/3)=>
$x ^{2} - 3x + 4 \\ \\ ( - \frac{1}{3} )^{2} - 3.( - \frac{1}{3} ) + 4 \\ \\ \frac{1}{9} + 1 + 4 \\ \\ \frac{1}{9} + 5 \\ \\ \frac{46}{9}$

c) f(√3)=>

\/3^2 -3\/3 + 4=>

3 - 3\/3 + 4=>

7 - 3\/3

d) f(1-√2)=>

(-2\/2)^2 + 3 * 1\/2 + 4=>

\/2^2 + 3\/2 + 4 =>

2 + 3\/2 + 4 =>

6 + 3\/2