(2)CE= 3

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Reason: A is AM⊥BC in M, D is DN⊥C in N,

AB = AC，DB=DE，∠BAD= 120

∴∠B=30，BN=EN，BM=CM，

∴cos∠B=BN

Bachelor of science

=BM

barium

= 3

2

∴BE= 3

BD，BC= 3

AB，

∠∠BDE =∠BAC，

∴DE∥AC，

∴AD

ab blood type

= EC

B.C.

∴AD

European Commission (European Commission)

=AB

B.C.

= 1

three

∴CE= 3

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(3) The quantitative relationship between CE and AD is CE=2sinα2.

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Proof: AB = AC, DB=DE,

∴AB

decibel

= communication

Delaware

.

∠∠BAC =∠BDE，

∴△ABC∽△DBE.

∴AB

decibel

= BC

exist

，∠ABC=∠DBE，

∴AB

B.C.

=DB

exist

，∠ABD=∠ABC-∠DBC=∠DBE-∠DBC=∠CBE，

∴△ABD∽△CBE，

∴AD

Church of England

=BD

exist

DF⊥BE with point D as point F.

∴∠BDF= 1

2

∠BDE=α

2

∴BE=2BF=2BD？ sin∠BDF=2BD？ sinα

2

∴AD

Church of England

= 1

2sinα

2

∴CE=2sinα

2

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