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Anestetic [448]
4 years ago
8

Prove Cos3x=cos^3(x)-3sin^2(x)cos(x)

Mathematics
1 answer:
vivado [14]4 years ago
3 0
\cos3x=\cos^3x-3\sin^2x\cos x\\\\L_s=\cos(2x+x)=\cos2x\cos x-\sin2x\sin x\\\\=(\cos^2x-\sin^2x)\cos x-2\sin x\cos x\sin x\\\\=\cos^3x-\sin^2x\cos x-2\sin^2x\cos x\\\\=\cos^3x-3\sin^2x\cos x=R_s\\\\\text{Used:}\\\\\cos(\alpha+\beta)=\cos\alpha\cos\beta-\sin\alpha\sin\beta\\\\\cos2\alpha=\cos^2\alpha-\sin^2\alpha\\\\\sin2\alpha=2\sin\alpha\cos\alpha
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olya-2409 [2.1K]
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Darina [25.2K]

Answer:

6 units squared

Step-by-step explanation:

To solve this problem you can solve for the entire area of the square and subtract the area of the unfilled areas for the area of the shaded region..

Area of entire square is 4*4=16

Now for the sections that are unfilled:

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Hope this helped!

7 0
4 years ago
Read 2 more answers
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pashok25 [27]
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Answer:

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