document.write( "Question 495480: Find all t in the interval [0, 2π] satisfying (cos t)2 + 10 cos t + 9 = 0. \n" ); document.write( "

Algebra.Com's Answer #336261 by lwsshak3(11628) $\"\"$ $\"About$

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Find all t in the interval [0, 2π] satisfying (cos t)2 + 10 cos t + 9 = 0
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\n" ); document.write( "Cos^2 t+10cos t+9=0
\n" ); document.write( "(cos t+9)(cos t+1)=0
\n" ); document.write( "Cos t=-9(reject, (-1 ≤ cos ≤ 1))
\n" ); document.write( "or
\n" ); document.write( "cos t=-1
\n" ); document.write( "t=π \n" ); document.write( "

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