Question

4 и 5 задание (смотрите на изображение)

Answer 1

$1. 13-12sin^2x=13-12 - 12cos^2x=1-12*0.11=1-1.32=-0.32$
$2. ctga = -4 \ tga = frac{1}{-4} \ tg^2a + 1 = frac{1}{cos^2a} \ frac{17}{16} = frac{1}{cos^2} \ cosa= frac{4}{ sqrt{17} }\ frac{ sqrt{17} }{ frac{4}{ sqrt{17} } }= frac{17}{4}=4.25$
$3. sqrt{6} *sin frac{63pi}{4} * tg frac{64pi}{3} = sqrt{6} *sin frac{7pi}{4} * tg frac{4pi}{3}= \ sqrt{6} *sin ( frac{3pi}{2} - frac{pi}{4}) * tg (pi + frac{pi}{3})= sqrt{6} *(-cos frac{pi}{4}) * tg frac{pi}{3}=\ sqrt{6} *(-frac{sqrt{2} }{2}) * sqrt{3}= -3$ 
$4 frac{1- 2sin^254}{8tg9 * sin^299} = frac{cos108}{8tg9 *cos9}= frac{cos108}{8sin9}= frac{-sin18}{sin9}= frac{-2sin9cos9}{8sin9}= frac{-cos9}{4}$$sqrt{2} * frac{sin40*cos5-cos40*sin5}{-(cos25cos35 - sin25sin35) }= sqrt{2} * frac{sin45}{cos60}= sqrt{2}* sqrt{2}=2$