Posted by **batmo** on Monday, September 24, 2012 at 12:06am.

Given Z = 2(cos 148° + isin 148°) and W = 5(cos 11° + isin 11°), find and simplify z/w.

10(cos 137° – isin 137°)

0.4(cos 137° + isin 137°)

0.4(cos 137° – isin 137°)

10(cos 137° + isin 137°)

- Calculus -
**Reiny**, Monday, September 24, 2012 at 12:33am
multiply top and bottom by the conjugate of the denominator, that is, multiply top and bottom by

(cos11 - isin11)

(I will skip the ° sign)

expand and simplify to get

(2/5) (cos148cos11 - icos148sin11 + isin148cos11 - i^2sin148sin11)/(cos^2 11 - i^2 cos^2 11)

= (2/5) (cos148cos11 - cos148sin11 + i(sin148cos11 - cos148sin11)/ 1

= .4( cos(148-11) + i(sin(148-11))

= .4(cos 137 + sin137)

which is one of the choices.

## Answer this Question

## Related Questions

- Calculus - Determine the polar form of the complex number 3 - 2i. Express the ...
- Trigonometry - There are four complex fourth roots to the number 4−4√...
- Complex angles - There are four complex fourth roots to the number 4−43&#...
- Math - Find the quotient of the following expression: 7(cos 5pi/6 +isin 5pi/6...
- Calculus II - What is sin(i) -- (sin of the imaginary number, i) What is cos(i...
- Integration by Parts - integral from 0 to 2pi of isin(t)e^(it)dt. I know my ...
- Math - Find the following product -5(cos pi/3 +isinpi/3)*2(cos pi/6+ isin pi/6' ...
- maths - 1. Prove using mathematical induction that 1+2+3+...+n=[ n(n+1)]/2 2. ...
- maths - 1. Prove using mathematical induction that 1+2+3+...+n=[ n(n+1)]/2 2. ...
- Math - Express -5(cos pi/2 +isin pi/2) in rectangular form. I got -5i. Is this ...