Saturday

February 28, 2015

February 28, 2015

Posted by **jon smith** on Monday, January 3, 2011 at 8:41am.

b) Polar form

Any help with this question would appreciated

- maths/ physics -
**Reiny**, Monday, January 3, 2011 at 9:11amlet the angle be Ø

then r = √(3^2+4^2) = 5

tanØ = 4/3, Ø = .9273

3 + 4j = 5(cos .9273 + jsin .9273)

by De Moivre's theorem

(3 + 4j)^(1/2) = √5(cos ((1/2).9273) + jsin ((1/2).9273))

= √5( cos .4636 + jsin .4636)

or 2 + j if expanded.

check:

if 2+j is the square root of 3+4j, then

(2+j)^2 should equal 3+4j

Left side = (2+j)^2

= 4 + 4j + j^2

= 4 + 4j - 1

= 3 + 4j

so √(3+4j) = 2+j or √5(cos .4636 + jsin .4636)

**Answer this Question**

**Related Questions**

calculus - for what value of r=4sinè have vertical tangent? In polar coordinates...

Maths - Polar Coordinate Systems - I've recieved an assignment to investigate ...

Math 12 - Hey everyone; There are some questions on my review I am having ...

Pre-Cal - Find the 5 roots of x^5+1=0 in polar and Cartesian form. (x^5 means x ...

Precalculus - "Show that x^6 - 7x^3 - 8 = 0 has a quadratic form. Then find the ...

complex numbers! - -2-2i in polar form = 2.8 cis 2.35?? -3+4i polar form = 5 cis...

Calc - Find a cartesian equation for the curve described by the given polar ...

PRECALCULUS - 1.) determine two pairs of polar coordinates for the point (-...

Maths - Solve for x (exact solutions): sin x - sin 3x + sin 5x = 0 ¦Ð ¡Ü x...

math - Express z = 1 + 2j in polar form then find z^3 then convert the answer to...