求解=.=

承b

1.Let r1 and r2 be the two real roots of the equation (x-2006)(x-2007)=2007. if r is the smaller real root of the equation (x-r1)(x-r2)=-2007,find the value of r.
2.the area of the largest rectangle with perimeter 1 metre is b square metre,find the value of b.

3.x^y+x^-y=(2)2^(1/2) and x^y-x^-y=k,where x>1 and y>0,find the value of k.

4.48^x=2 48^y=3  if 8^((x+y)/(1-x-y))=b find the value of b.

5.suppose x^(1/2)+x^(-1/2)=3 and b=(x^(3/2)+x^(-3/2)-3)/(x^2+(x^-2)-2),find the value of b.

唔比用計數機help= =

-終場ソ使者-

1)
What is b?
2)
just form a suitable equation to find the relevant length and width!
3)


Therefore,                        (*)


k=2 or -2                       from (*)
for x>1 and y>0,



4)


considering ,
therefore

5)

So                                    (*)
consider ,


consider ,                            from (*)
thus
b=1/3

承b

sorry= =,打錯野,第1題果個r黎,,你好勁,解左幾耐= =