Question

va rooog repede exercitiul 4

Answer 1

Răspuns

a) asa este

b) b=2

a²-b²=8-4=4

Explicație pas cu pas:

a=1/√2+2/2√2 +3/3√2+4/4√2=

1/√2+1/√2+1/√2+1/√2=4/√2=4√2/2=2√2

b=12/6=2

a²-b²=8-4=4

Answer 2

$\it \sqrt8=\sqrt{4\cdot2} =2\sqrt2\\ \\ \sqrt{18}=\sqrt{9\cdot2} =3\sqrt2\\ \\ \sqrt{32}=\sqrt{16\cdot2} =4\sqrt2$

$\it a = \dfrac{1}{\sqrt2}+ \dfrac{\ 2^{(2}}{2\sqrt2}+ \dfrac{\ 3^{(3}}{3\sqrt2}+ \dfrac{\ 4^{(4}}{4\sqrt2} = \dfrac{1}{\sqrt2}+\dfrac{1}{\sqrt2}+\dfrac{1}{\sqrt2}+\dfrac{1}{\sqrt2}=4\cdot \dfrac{1}{\sqrt2}=\\ \\ \\ =\dfrac{\ ^{\sqrt2)}4}{\ \ \sqrt2}= \dfrac{4\sqrt2}{2} =2\sqrt2$

$\it b=\dfrac{\sqrt{13^2-5^2}}{\sqrt{10^2-8^2}} = \dfrac{\sqrt{169-25}}{\sqrt{100-64}} =\dfrac{\sqrt{144}}{\sqrt{36}}=\dfrac{12}{6}=2\\ \\ \\ a^2-b^2=(2\sqrt2)^2-2^2=4\cdot2-4=8-4=4$