1)cost/(1+cost)+cost/(1-sint)=((cost(1-sint+1+sint))/(1+sint)*(1-sint)=2cost/cos^2t=2/cost
2)tqx+1/(1-ctqx)=1/ctqx+1/(1-ctqx)=(1-ctqx+ctqx)/(ctqx(-ctqx)=1/(ctqx-ctq^2x)
Ответ:
b(x)=x2-6x+4
m = = -
m = b(3) = 9 - 6 * 3 + 4 = 13 - 18 = - 5
Ответ: (3 ; -5)
Уравнение 55 + 22,6*х=(49+14,2*х)*0,4 , где х число дней
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<span>2log(1/3)6 - 1/2log(1/3)400 + 3log(1/3) ³√45 =
= log (1/3)6^2 - log(1/3)</span>√(400) + log(1/3)(∛45)^3 =
= log(1/3) 36 - log (1/3) 20 + log(1/3) 45 =
= log (1/3) (36/20) + log (1/3) 45 =
= log (1/3) (9/5) + log (1/3) 45 =
= log (1/3) ((9*45)/5) =
= log (1/3) 81 =
= log 3^(-1) 3^4 =
= - log 3 3^4 = - 4
А12=а1+11d
a23=a1+22d
выразим а1 в первом выражении и подставим во второе а1=а12-11d
a23=a12-11d+22d
a23-a12=11d
1-(-21)=11d
22=11d
d=22:11
d=2