Question

So sánh:

a) \(\sqrt{4^2}\) và \(\left|4\right|\);                       b) \(\sqrt{\left(-5\right)^2}\) và \(\left|-5\right|\).

Answer 1

a. Ta có: \(\sqrt {{4^2}}  = \sqrt {16}  = 4\)

                \(\left| 4 \right| = 4\)

Vậy \(\sqrt {{4^2}}  = \left| 4 \right|\).

b. Ta có: \(\sqrt {{{\left( { - 5} \right)}^2}}  = \sqrt {25}  = 5\)

                \(\left| { - 5} \right| = 5\)

Vậy \(\sqrt {{{\left( { - 5} \right)}^2}}  = \left| { - 5} \right|\).