<span>5sin²x + cosx - 1 = 0</span>
5( 1 - cos²x) + cosx - 1 = 0
5 - 5cos<span>²x </span>+ cosx - 1 = 0
- 5cos²x + cosx + 4 = 0 /:(-1)
5cos²x - cosx - 4 = 0
(5cosx + 4)(cosx - 1) = 0
cosx = 1 ==> x = 2pik, k ∈ Z
cosx = - 0,8 ==> x = ± (pi - arccos(0,8)) + 2pik, k ∈ Z
-4р в 4 степени+12р в 3 степени-5р в 3 степени
Ответ:
Объяснение:при у=1/3, 1/3х+8=1/3
1/3х= -7 2/3= -23/3
х= -23/3 ÷1/3= -23/3×3/1= -23
при у=0,3 1/3х+8=0,3
1/3х= -7,7= -7 7/10= -77/10
х= -77/10÷1/3= -77/10×3/1= -231/10= -23,1
при х=8 , 1/3х+8=8
1/3х=8-8=0
х=0
при х=30, 1/3х+8=30
1/3х=22
х=22÷1/3=22×3=66
1)а/(0,5а+1)+(2/3 а)/(2-а)+2а/(1/4 а^2-1)=2a/(a+2)-2a/3(a-2)+8a/(a-2)(a+2)=
=(6a²-12a-2a²-4a+24a)/3(a²-4)=(4a²+8a)/3(a²-4)=4a(a+2)/3(a-2)(a+2)=
=4a/3(a-2)
2)4a/3(a-2)*(0,5а-1)/(2,5а-2)=4a/3(a-2)*(a-2)/(5a-4)=4a/(15a-12)