# student2280

## 解答 0

• eric
2019-05-20 19:27:34
24. Use tan2θ=2tanθ/(1-tan^2 θ)
• eric
2019-05-20 20:02:34
26. Use cos(4θ) = cos^4(θ) - 6cos2^(θ)sin2(θ) + sin^4(θ) and (sin^2(θ)+cos^2(θ))^2=1
• eric
2019-05-20 20:08:07
28a. Expand 3/(csc^2(θ)+1) using sin2θ formula
• eric
2019-05-20 20:09:31
28b. Use the range of csc^2(θ)
• eric
2019-05-20 20:14:18
Use the minimum of csc^2(2θ)
•  eric 2019-05-20 20:09:31
• 28b. Use the range of csc^2(θ)
• student2280
2019-05-21 16:18:32
I have used ,but i dont know how to do the next step
•  eric 2019-05-20 19:27:34
• 24. Use tan2θ=2tanθ/(1-tan^2 θ)
• student2280
2019-05-21 16:38:59
I dont know how to use the range
•  eric 2019-05-20 20:09:31
• 28b. Use the range of csc^2(θ)
• eric
2019-05-21 16:41:36
2tanθ/(1-tan^2 θ)=√3 √3tan^2 θ+2tanθ-√3=0 Then solve for tanθ
•  student2280 2019-05-21 16:18:32
• I have used ,but i dont know how to do the next step
• student2280
2019-05-21 16:46:35
I dont know how to do the next step

#### 附加文件

•  eric 2019-05-20 20:08:07
• 28a. Expand 3/(csc^2(θ)+1) using sin2θ formula
• eric
2019-05-21 16:48:01
the range of csc^2(2θ) is 1 to ∞ Substituting 1 into the expression will give the answer
•  student2280 2019-05-21 16:38:59
• I dont know how to use the range
• eric
2019-05-21 16:59:23
the second last step is wrong as sin^2(2θ)=4sin^2(θ)cos^2(θ)
•  student2280 2019-05-21 16:46:35
• I dont know how to do the next step
• student2280
2019-05-21 17:16:15
Thank a lots
• student2280
2019-05-21 17:16:32
Thank a lot
• eric
2019-05-21 17:18:52
Not at all
•  student2280 2019-05-21 17:16:32
• Thank a lot

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