Friday

September 19, 2014

September 19, 2014

Posted by **Shin** on Monday, May 27, 2013 at 7:06am.

z1=r1(cosθ1+isinθ1)

z2=r2(cosθ2+isinθ2)

z3=r3(cosθ3+isinθ3)

z4=r4(cosθ4+isinθ4),

where ri is a real number and 0∘≤θi<360∘. What is the value of θ1+θ2+θ3+θ4 (in degrees)?

- Trigonometry -
**Reiny**, Monday, May 27, 2013 at 9:14amlet z = 4-4√3 i

then by De Moivre's theorem

tanØ = -4√3/4 = -√3

so that Ø = 120° or Ø = 300°

z = 8(cos 120° + i sin120°) or z = 8(cos 300° + i sin300°)

case1:

then z^(1/4) = 8^(1/4) (cos 30° + i sin30°)

but for tanØ = -4√3/4 , recall that the period of tanØ is 180°

so adding 180° to our angle yields another solution

making z(1/4) = 8^(1/4) (cos 210° + i sin 210°)

so far we have Ø1=30° , Ø2 = 210°

cose2:

z^(1/4) = 8(1/2)( cos 300/4 + i sin 300/4) = 8(1/4) (cos 75 + i sin 75)

and with a period of 180° again,

z^(1/4) could also be 8^(1/4)(cos 255° + i sin 255°)

giving us Ø3 = 75 and Ø4 = 255

**Ø1+Ø2+Ø3+Ø4 = 30+210+75+255 = 570°**

- Trigonometry -
**K**, Sunday, June 2, 2013 at 7:57pmwrong man

**Answer this Question**

**Related Questions**

Complex angles - There are four complex fourth roots to the number 4−43&#...

Math - Calculus - The identity below is significant because it relates 3 ...

Trigonometry - Which of the following is equivalent to 1 − cos 2 θ/...

trigonometry - if cosθ=2/3 and tanθ<0 find the exact value sin(&#...

math - if cosθ=2/3 and tanθ<0 find the exact value sin(θ-5&#...

trig - An object Is propelled upward at an angle θ, 45° < θ<90...

Calculus AP - hi again im really need help TextBook: James Stewart:Essential ...

Pre-Calculus - If θ represents an angle such that sin2θ = tanθ - ...

Trig - Given that csc θ = -4 and tan θ > 0, find the exact value of...

Trig - Given that tan θ = - (√3/8) and θ is in QII, find the ...