To solve (3−i)4, we can use De Moivre's Theorem, which is useful when raising complex numbers to a power. Here's the step-by-step process:
Convert the complex number to polar form:
A complex number z=a+bi can be represented in polar form as:
z=r(cosθ+isinθ)
where r=a2+b2 is the magnitude and θ=tan−1(ab) is the argument.
Since tan−1(31)=6π, and the point lies in the fourth quadrant:
θ=−6π
So, in polar form:
3−i=2(cos(−6π)+isin(−6π))
Apply De Moivre's Theorem: zn=rn(cos(nθ)+isin(nθ))
Substituting r=2, θ=−6π, and n=4:
(3−i)4=24(cos(4×−6π)+isin(4×−6π))=16(cos(−64π)+isin(−64π))
Simplify the angle:
=16(cos(−32π)+isin(−32π))
Evaluate the trigonometric functions: cos(−32π)=−21,sin(−32π)=−23
Therefore:
(3−i)4=16(−21−i23)=16(−21−i23)=−8−83i
So, the result is:
(3−i)4=−8−83i
Would you like further details or have any questions?
Here are five questions related to this topic:
How does De Moivre's Theorem help in simplifying powers of complex numbers?
What is the significance of the polar form of a complex number?
How do you determine which quadrant a complex number lies in?
What are the steps to convert a complex number from rectangular to polar form?
How does the argument of a complex number change when raised to a power?
Tip: When working with complex numbers, always check the quadrant to ensure correct angle measurements.