" 5.If "lim_(x rarr-sqrt(x+2)-sqrt(2a))=sqrt(2)" (where a e "R^(+)" ),then a is equal to "

lim_(x rarr2)(x-2)/(sqrt(x)-sqrt(2))

lim_(x rarr2)(5)/(sqrt(2)-sqrt(x))

lim_(x rarr2)(5)/(sqrt(2)-sqrt(x))

lim_(x rarr0)(sqrt(2+x)-sqrt(2))/(x)

lim_(x rarr0)(x)/(sqrt(2+x)-sqrt(2))

lim_(x rarr0)(sqrt(2-x)-sqrt(2+x))/(x)

lim_(x rarr oo){sqrt(x+1)-sqrt(x)}sqrt(x+2)

lim_(x rarr0)(sqrt(1-cos2x))/(sqrt(2)x)

lim_(x rarr a)(2x-sqrt(x^(2)+3a^(2)))/(sqrt(x+a)-sqrt(2a))=sqrt(2) (where a in R^(+), then a is equal to -

lim_(x rarr2)(x-2)/(sqrt(x+2)-sqrt(3x-2))