Упростить выражение 2sin(3π/2 +α) *sin(π+α) +tq(π+α)*ctq(2π-α)
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применим формулы приведения :
2sin(3π/2 +α) *sin(π+α) +tq(π+α)*ctq(2π-α) =2*(-cosα)*(-sinα) +tqα*(-ctqα) =
2sinαcosα -tqα*ctqα =sin2α -1.
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sin2α -1 = -(sinα -cosα)².
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sin2α -1= -(1 -sin2α) = -(1-cos(π/2 -2α)) = -2sin²(π/4 -α).
=29 балов =
<span>0,37-1/4=0,37-0,25=0,12
</span><span>9/16+3,23=0,5625+3,23=3,7925
</span><span>4(целых)9/25+6,37=4,36+6,37=10,73
</span><span>12(целых)9/40-7,84=12,225-7,84=4,385
</span><span>8(целых)5/16-5,49=8,3125-5,49=2,8225</span>
<span>1#8 ✖ 7 равно #56 знначит берём 108 умножить на 7 =756</span>
1)230+20=250
2)230+250=480
3)480+40=520
4)230+250+520=1000
<span>1)</span>3а+8а=1,87
<span>11а=1,87 </span>
<span>а=1,87/11 </span>
<span>а=0,17</span>
2)<span>7 z - 3z = 5,12 </span>
<span>z * (7 - 3) = 5,12 </span>
<span>4z = 5,12 </span>
<span>z = 5,12 / 4 </span>
<span>z= 1,28</span>
3)<span>2t + 5t + 3,18 = 25,3 </span>
<span>2t + 5t = 25,3 - 3,18 </span>
<span>t(2+5) = 22,12 </span>
<span>7t = 22,12 </span>
<span>t = 22,12 / 7 = 3,16</span>