document.write( "Question 929749: using the double angle formula, find the exact value of sin(2x) given sinx=-(5/8) and tan x>0 \n" ); document.write( "

Algebra.Com's Answer #564463 by lwsshak3(11628) $\"\"$ $\"About$

You can put this solution on YOUR website!
using the double angle formula, find the exact value of sin(2x) given sinx=-(5/8) and tan x>0
\n" ); document.write( "***
\n" ); document.write( "Reference angle x is in quadrant II where sin<0, cos<0
\n" ); document.write( "sinx=-5/8
\n" ); document.write( "cosx=√(1-sin^2(x))=√(1-(25/64))=√(39/64)=√39/8
\n" ); document.write( "sin(2x)=2sinxcosx=2*(-5/8)(√39)/8=-10√39/64 \n" ); document.write( "

\n" );