How do I simplify: i^7, i^28, i^76?
A-Best: The important things to remember here are
(1) i^4 = 1 , and
(2) i^(r + q * m) = (i^r) * ((i^m)^q) .
Say we want to simplify i^n for some positive integer n. Using the division algorithm, we may find numbers q and r (the quotient and remainder) where 0 ≤ r < 4 such that
n = r + 4 * q .
Thus
i^n = i^(r + 4 * q) = (i^r) * (i^4)^q = i^r .
In other words, we just need to look at the remainder left after division by 4, and compute i raised to that remainder. The remainder will be one of 0, 1, 2, or 3, and so we just need to know that
i^0 = 1, i^1 = i, i^2 = -1, and i^3 = -i .
We have
7 = 3 + 4 * 1 , 28 = 0 + 4 * 7 , and 76 = 0 + 4 * 19 ,
and so compute that
i^7 = i^3 = -i and i^(28) = i^(76) = 1 .
A: i = i
i^2 = -1
i^3 = -i
i^4 = 1
then pattern repeats
so i^7 = i^3 = -i
i^28 = i^4 = 1
i^76 = i^4 = 1 (28 and 76 are both multiples of 4)
A: Powers of i are a repeating pattern:
i¹=i
i²=-1
i³=-i
i⁴=1
i⁵ is just i⁴*i, and since i⁴=1, i⁵=(1)i, or simply, i.
You can use the same concept for i⁷, i²⁸, and i⁷⁶
i⁷=(i⁴)(i³)=(1)i³=i³=-i
i²⁸=(i⁴)⁷=(1)⁷=1
i⁷⁶=(i⁴)¹⁹=(1)¹⁹=1
Hope that helps!
A: i^7=i^4.i^3
=1.i^3
=-i because i^4=1,i^3=-i
i^28=(i^4)^7=1^7=1
i^76=(i^4)^19=1
A: i^2 = -1
i^3 = i*i^2 = -i
i4 = i^2 * i^2 = 1
i^7 = i^3 * i ^4 = -i * 1 = -i
i^28 = i^4*i^4*i^4*i^4*i^4*i^4*i^4 = 1
i^76 = i^28*i^28*i^4*i^4*i^4*i^4*i^4 = (1)(1) = 1
A: the definition of i is the square root of -1, so
i^2 = -1,
i^3 = i*i^2 = -i,
i^4 = i^2*i^2 = 1
So i^7=i^3*i^4 = -1
i^28 = i^(4*7) = 1
i^76 - i^(4*19) = 1
A: i² = -1
i³ = -i
i^4 = 1
i^7 = (i^4)(i^3) = (1)(-i) = -i
i^28 = (i^4)^7 = (1)^7 = 1
i^76 = (i^4)^19 = (1)^19 = 1
Answer: i^7 = -i, i^28 = 1, and i^76 = 1