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B(3+2.2)<span>≤1 5.2b</span><span>≤1 b=1/5.2
</span>b>-5 b>-5 <span> </span><span><span>b>-5 </span>
Ответ:1/5,2=5/26
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1) cos5α-cosα = -2sin2α*sin3α ;
2) cosα - cos3α +2sin2α = 2sinα *sin2α +2sin2α =2sin2α*(sinα+1) =
2sin2α(1 +cos(π/2 -α)) =4sin2α*cos² (π/4 - α/2).
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cosα - cos3α +2sin2α = 2sinα *sin2α +2sin2α =2sin2α*(sinα+1) =
2sin2α(sinα+sinπ/2) =4sin2α*sin(π/4 +α/2)*cos(π/4 -α/2) =
[[ но *** sin(π/4 +α/2) =cos(π/2 -(π/4 +α/2)) =cos(π/4 - α/2) *** ]] =
4sin2α*cos² (π/4 - α/2).
(5p + 3q - 2q)(5p + 3q + 2q) = (5p + q)(5p + 5q) = (5p + q) * 5 (p + q) = 5(5p + q)(p + q)