X^20*x^9:x^4/x^20*x^3=x^25/x^23=x^2
х4(х-2)+4х2(х-2х)+3(х-2)= (х4+4х2+3)(х-2)
1) cos a cos 3a - sin a sin 3a = cos (a+3a) = cos 4a
2) sin 2a cos a + cos 2a sin a = sin (2a+a) = sin 3a
3) sin40°cos5°+cos40°sin5° = sin(40°+5°)= sin 45° =
4)
5)
-10-10х-16-9>0
-10х>35
х<3,5
(3,8*0,001)(8*0,001)=0,0000304