document.write( "Question 435392: solve cos15 without using calculater \n" ); document.write( "
Algebra.Com's Answer #301363 by lwsshak3(11628)![]() ![]() ![]() You can put this solution on YOUR website! solve cos15 without using calculater \n" ); document.write( "use cos 1/2 angle formula: \n" ); document.write( "cos s/2=+-sqrt((1+cos s)/2) \n" ); document.write( "cos15=cos(30/2)=(sqrt(1+cos30)/2) \n" ); document.write( "sqrt((1+sqrt(3)/2)/2) \n" ); document.write( "sqrt(2+sqrt(3)/2 (Note: solution positive because cos 15 in quad I is positive) \n" ); document.write( " |