document.write( "Question 1114896: Given: cos (-105)
\n" ); document.write( "Find the exact value of the function without the use of a calculator.\r
\n" ); document.write( "\n" ); document.write( "I was unsure what to do with a negative, but from examples, I did the following where it \"ignores\" the negative.\r
\n" ); document.write( "\n" ); document.write( "cos (105) = cos (135 - 30)
\n" ); document.write( " $\"+cos+%28135%29+cos+%2830%29+%2B+sin+%28135%29+sin+%2830%29+\"$
\n" ); document.write( " $\"+%28-sqrt%282%29%2F2%29%28sqrt%283%29%2F2%29+%2B+%28sqrt%282%29%2F2%29%281%2F2%29+\"$
\n" ); document.write( " $\"+%28-sqrt%286%29%2F4%29%2B+%28sqrt%282%29%2F4%29+\"$
\n" ); document.write( "Final Answer: $\"+%28sqrt%282%29-sqrt%286%29%29+%2F+%284%29+\"$ \r
\n" ); document.write( "\n" ); document.write( "If the final answer is right, why does the (-) go away and if that procedure is incorrect how would you split up the -105? Thank you for any help! \n" ); document.write( "

Algebra.Com's Answer #853702 by MathTherapy(10719) $\"\"$ $\"About$

You can put this solution on YOUR website!

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document.write( "Given: cos (-105)\r\n" );
document.write( "Find the exact value of the function without the use of a calculator.\r\n" );
document.write( "\r\n" );
document.write( "I was unsure what to do with a negative, but from examples, I did the following where it \"ignores\" the negative.\r\n" );
document.write( "\r\n" );
document.write( "cos (105) = cos (135 - 30) \r\n" );
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document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Final Answer: \r\n" );
document.write( "If the final answer is right, why does the (-) go away and if that procedure is incorrect how would you split up\r\n" );
document.write( "the -105? Thank you for any help! \r\n" );
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document.write( "You're applying the DIFFERENCE of 2 angles here, which does give you \r\n" );
document.write( ". However, the NEGATIVE is NOT IGNORED/does NOT just DISAPPEAR.\r\n" );
document.write( "\r\n" );
document.write( " <==== You got up to this point\r\n" );
document.write( ", which is EQUAL to, or the SAME as:  . \r\n" );
document.write( "YOUR Final Answer: \r\n" );
document.write( "Looking at the 2 expressions ABOVE, one can clearly see that they're the SAME.\r\n" );
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document.write( "**Note:\r\n" );
document.write( "You asked how the cos (- 105) could be SPLIT, if your answer is incorrect. Your answer isn't incorrect, as stated \r\n" );
document.write( "above, but another SPLIT would be cos (- 105) = cos (- 60 - 45), or {cos [(- 60) + (- 45)]}, which would then\r\n" );
document.write( "involve the SUM of 2 angles. Nonetheless, this yields the same result!

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