document.write( "Question 170929: Determine the values of sin2x, cos2x, and tan2x:\r
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Algebra.Com's Answer #126222 by Edwin McCravy(20059)\"\" \"About 
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Determine the values of \"Sin%282x%29\", \"Cos%282x%29\", and \"Tan%282x%29\":
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document.write( "\"Sin%28x%29=3%2F5\", and x is acute\r\n" );
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document.write( "Since \"SINE=%28OPPOSITE%29%2F%28HYPOTENUSE%29\"\r\n" );
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document.write( "We can let the opposite side be the numerator of \"3%2F5\",\r\n" );
document.write( "which is \"3\", and the hypotenuse be the denominator\r\n" );
document.write( "of \"3%2F5\" which is \"5\", so we draw this picture:\r\n" );
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document.write( "Now we find the adjacent side by the Pythagorean theorem:\r\n" );
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document.write( "\"hypotenuse%5E2=opposite%5E2%2Badjacent%5E2\"\r\n" );
document.write( "\"5%5E2=3%5E2%2Badjacent%5E2\"\r\n" );
document.write( "\"25=9%2Badjcent%5E2\"\r\n" );
document.write( "\"16=adjacent%5E2\"\r\n" );
document.write( "\"sqrt%2816%29=sqrt%28adjacent%5E2%29\"\r\n" );
document.write( "\"4=adjacent\"\r\n" );
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document.write( "So we label the adjacent side as \"4\"\r\n" );
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document.write( "To find \"Sin%282x%29\", we use this identity:\r\n" );
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document.write( "\"sin%282x%29=2sin%28x%29Cos%28x%29\"\r\n" );
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document.write( "We are given \"Sin%28x%29=3%2F5\" but we do not have \"Cos%28x%29\".\r\n" );
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document.write( "Since \"COSINE=%28ADJACENT%29%2F%28HYPOTENUSE%29\"\r\n" );
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document.write( "\"Cos%28x%29=4%2F5\"\r\n" );
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document.write( "\"sin%282x%29=2sin%28x%29Cos%28x%29\"\r\n" );
document.write( "\"sin%282x%29=2%283%2F5%29%284%2F5%29\"\r\n" );
document.write( "\"sin%282x%29=2%2812%2F25%29\"\r\n" );
document.write( "\"sin%282x%29=24%2F25\"\r\n" );
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document.write( "To find \"Cos%282x%29\", we use this identity:\r\n" );
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document.write( "\"Cos%282x%29=Cos%5E2x+-+Sin%5E2x\"\r\n" );
document.write( "\"Cos%282x%29=%284%2F5%29%5E2-%283%2F5%29%5E2%0D%0A%7B%7B%7BCos%282x%29=16%2F25-9%2F25\"\r\n" );
document.write( "\"Cos%282x%29=7%2F25\".\r\n" );
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document.write( "To find \"+Tan%282x%29+\", we can use this identity:\r\n" );
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document.write( "\"Tan%282x%29=%28+Sin%282x%29+%29%2F%28+Cos%28x%29+%29+\"\r\n" );
document.write( "\"Tan%282x%29=%2824%2F25%29%2F%287%2F25%29\"\r\n" );
document.write( "\"Tan%282x%29=%2824%2F25%29%2A%2825%2F7%29\"\r\n" );
document.write( "\"Tan%282x%29=%2824%2Fcross%2825%29%29%2A%28cross%2825%29%2F7%29\"\r\n" );
document.write( "\"Tan%282x%29=24%2F7\"\r\n" );
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document.write( "Edwin
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