document.write( "Question 1093833: Write the sum as a product using a sum-to-product identity.
\n" ); document.write( "sin (-α) + sin (19α)\r
\n" ); document.write( "\n" ); document.write( "Select one:
\n" ); document.write( "a. 2 cos (-2α)sin(-10α)
\n" ); document.write( "b. 2 sin (-2α)cos(-10α)
\n" ); document.write( "c. 2 sin (-2α)sin(-10α)
\n" ); document.write( "d. 2 sin (9α)cos(-10α) \n" ); document.write( "

Algebra.Com's Answer #708567 by Alan3354(69443) $\"\"$ $\"About$

You can put this solution on YOUR website!
See \"Half angle formulas\" on Wikipedia.
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