Physics, asked by chanchalsaini23, 9 months ago

ABCDE is a Pentagon .prove that
ab + bc + cd + de + ea = 0

Answers

Answered by SonalRamteke
4

ApplyingtrinagleruleofvectoradditioninthetriangleABC,weget

AC

=

AB

+

BC

−−−(1)

Similarly,intriangleADEandtriangleACDweget

DA

=

DE

+

EA

−−−−(2)

AC

=

CD

+

AD

−−−−(3)

Therefore,

AB

+

BC

+

CD

+

DE

+

EA

Letusgrouptheaboveexpression,

(

AB

+

BC

)+

CD

+(

DE

+

EA

)

=

AC

+

CD

+

DA

Substitutingequation(1)

=

AD

+

DA

=

AD

AD

=0

Hence,proved.

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