∫dx/(4+8x-x²)=∫dx/[20-(x-4)²]=∫dx/[20(1-(x-4)²/20]=1/20*∫dx/[1-(x-4)²/20]=
=2√5/20*1/tg[(x-4)/2√5]+C=1/2√5*1/tg[(x-4)/2√5]+C
9×4= 9+9+9+9
38×2= 38+38
68:2= 68-34
V=π∫( от π\4 до π\2)сos²xdx=π(cos³x)\3( от π\4 до <span>π\2)=
</span>π\3(cos³π\2-<span>cos³</span>π\4)=π\3(0-√2\4)=3√2\12