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(secα)^2=2(secβ)^2如何得到1-(sinβ)^2=2[1-(sinα)^2].

题目详情
(secα)^2=2(secβ)^2如何得到1-(sinβ)^2=2[1-(sinα)^2].
▼优质解答
答案和解析
(secα)^2=2(secβ)^2
1/(cos α)^2=2/(cos β)^2
2(cos α)^2=(cos β)^2
2[1-(sinα)^2]=1-(sinβ)^2