urgent 谁会，帮帮忙，我的脑转不过来

非你不嫁

1.express square root 44-24square root 2 in the form a+b square root 2 and state the value of a and b...
2.solve the eqution x^1/2+x^-1/2=2(x^1/2-x^-1/2)
3.given that p^1/2-p^-1/2=2,show that p+p^-1=6
4.given that 2^a=3^b=18^c,show that ab=c(b+2a)





plssssssssssssssssssssssssssssssss help me.....urgent

乙劍真人

1.express square root 44-24square root 2 in the form a+b square root 2 and state the value of a and b.

學子

1.express square root 44-24square root 2 in the form a+b square root 2 and state the value of a and  ...
非你不嫁 发表于 23-5-2010 05:16 PM

44-24 Square root 2 = 20 Square root 2


如果我沒錯的話

乙劍真人

2.solve the eqution x^1/2+x^-1/2=2(x^1/2-x^-1/2)

乙劍真人

3.given that p^1/2-p^-1/2=2,show that p+p^-1=6

乙劍真人

4.given that 2^a=3^b=18^c,show that ab=c(b+2a)

Lov瑜瑜4ever

Q3) given that p^1/2-p^-1/2=2,show that p+p^-1=6

p^1/2-p^-1/2=2
p+1/p-2(p^1/2)[1/(p^1/2)]=4 (square both side)
p+1/p-2=4 (arrange)
p+1/p=6 (shown)

乙劍真人

Q3) given that p^1/2-p^-1/2=2,show that p+p^-1=6

p^1/2-p^-1/2=2
p+1/p-2(p^1/2)[1/(p^1/2)]=4 (squ ...
Lov瑜瑜4ever 发表于 23-5-2010 07:25 PM

嗯，根据题目 Given ..., show that ...

的确应该这样解，干净利落，佩服..^^

Lov瑜瑜4ever

Q2) solve the equation x^1/2+x^-1/2=2(x^1/2-x^-1/2)

x^1/2+x^-1/2=2(x^1/2-x^-1/2)
(x^1/2+x^-1/2)(x^1/2+x^-1/2)=2(x^1/2-x^-1/2)(x^1/2+x^-1/2)  (both side multiple x^1/2+x^-1/2)
x+1/x+2=2(x-1/x)
x+1/x+2=2x-2/x
x-3/x-2=0
x^2-2x-3=0
(x-3)(x+1)=0
x=3 or x=-1
but only x=3 is accepted if x is an element of N
because x=-1 will make x^1/2 become complex number,i

Lov瑜瑜4ever

嗯，根据题目 Given ..., show that ...

的确应该这样解，干净利落，佩服..^^
乙劍真人 发表于 23-5-2010 07:30 PM

多谢
彼此彼此切磋。。。

Lov瑜瑜4ever

1.express square root 44-24square root 2 in the form a+b square root 2 and state the value of a and b...

这个我也有个方法...

  [44-24(2^1/2)]^1/2
=(4^1/2)[11-6(2^1/2)]^1/2 (把4^1/2抽出来)
=2[11-2(18^1/2)]^1/2
=2[9-2(9x2)^1/2+2]^1/2
=2[3^2-2x3x(2^1/2)+(2^1/2)^2]^1/2 (弄成a^2-2ab+b^2的形式)
=2{[3-(2^1/2)]^2}^1/2 (a^2-2ab+b^2=(a-b)^2)
=2[3-(2^1/2)]
=6-2(2)^1/2

哈哈
我看到都有点乱
paiseh~

非你不嫁

wa...
all expert
thx u all ya...^^