document.write( "Question 421979: Please help me simplify this equation: (4-2i)/(7+3i) \n" ); document.write( "
Algebra.Com's Answer #294610 by Theo(13342)![]() ![]() You can put this solution on YOUR website! your expression is (4-2i) / (7 + 3i)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "I initially thought this was a multiplication, but I now see it's a division.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "you would want to remove the i terms from the denominator.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "if you multiply both numerator and denominator by (7-3i), that should do it.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "your expression becomes:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "(4-2i) * (7-3i) divided by (7+3i) * (7-3i)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "(7+3i) * (7-3i) would be equal to 49 - 21i + 21i - 9i^2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the middle terms cancel out and you are left with 49 -9i^2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the i's are treated like any other variable until the end, at which time they are finally processed based on the rules for i processing to be described after all is said and done.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "anyway, your denominator is 49 - 9i^2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "you would multiply your numerator out to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "(4-2i) * (7-3i) = 28 - 12i - 14i + 6i^2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "combine like terms to get your numerator equal to 28 - 26i + 6i^2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "your expression now has become:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "28 - 26i + 6i^2 divided by 49 - 9i^2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "now you process the i's based on the rules.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i = i \n" ); document.write( "i^2 = -1 \n" ); document.write( "i^3 = -i \n" ); document.write( "i^4 = 1\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "this is a cyclical pattern that repeats every 4 exponents.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i^5 = i \n" ); document.write( "i^6 = -1 \n" ); document.write( "i^7 = -i \n" ); document.write( "i^8 = 1\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i^9 = i \n" ); document.write( "i^10 = -1 \n" ); document.write( "i^11 = -i \n" ); document.write( "i^12 = 1\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "etc.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "your expression is, once again:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "28 - 26i + 6i^2 divided by 49 - 9i^2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "since i^2 is equal to -1, you change your expression to become:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "28 - 26i + 6*(-1) divided by 49 - 9*(-1)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "this simplifies to:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "28 - 26i - 6 divided by 49 + 9\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "combine like terms to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "22 - 26i divided by 58\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "divide both numerator and denominator by 2 to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "11 - 13i divided by 29\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "that should be your answer if i did it right.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "here's a decent reference that pretty much tells you the same thing.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "http://www.sparknotes.com/math/algebra2/complexnumbers/section3.rhtml\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "you remove the complex number from the denominator by multiplying the numerator and the denominator by the conjugate of the denominator.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "if the denominator is a + bi, then the conjugate is a - bi\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "if the denominator is a - bi, then the conjugate is a + bi\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "both the numerator and the denominator have to be multiplied by the same factor in order to preserve the integrity of the expression.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "2/4 * 2/2 = 4/8\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the integrity of the expression is maintained because 4/8 is equivalent to 2/4.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "between what i told you and the reference, you should get the idea.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |