Maths 快答

L.H.S. = (-2)^2n
= [(-2)^2]^n
= (4)^n
= [(2)^2]^n
= (2)^2n
= R.H.S. , for n is al natural number
所以 n can be any natural number

*另想問n 係positive 同negetive 有冇關系?, 無關係

你想知(-2)^2n = (2)^2n 係唔係岩?

你要先證明下佢先

左方(L.H.S.) = (-2)^2n
= 4^n

右方(R.H.S.) = (2)^2n
= 4^n

左方(L.H.S.) = 右方(R.H.S.)

n係positive同negetive冇關系

因為佢個n已經係一樣

如果個n係negetive

你let個n係-1你就知

左方(L.H.S.) = (-2)^2(-1)
= (-2)^(-2)
= 1/4

右方(R.H.S.) = (2)^2(-1)
= 2^(-2)
= 1/4

左方(L.H.S.) = 右方(R.H.S.)

所以n係positive同negetive係冇關系

(-2)^2n = (2)^2n 係岩既.

LHS = (-2)^2n = 4^n

RHS = (2)^2n = 4^n

LHS = RHS

考試2個方法都可以用來present.

n係positive同negetive冇關系.

(abc)^n = (a^n)(b^n)(c^n)
(-2)^2n = (-1)^2n。2^2n = 2^2n