9. In triangle ABC, right-angled at B, if an A= 1/√3,
find the value of:

(i) sin A cos C +cos A sin C
(ii) co

1 thought on “9. In triangle ABC, right-angled at B, if an A= 1/√3,<br />find the value of:<br /><br />(i) sin A cos C +cos A sin C<br />(ii) co”

1. In △ABC,

   ∠B=90o

   , tanA= 31

   = ABBC

   Let BC =1x,AB= 3x

   AC

   2

   =AB

   2

   +BC

   2

   AC

   2

   =(

   3

   x)

   2

   +(x)

   2

   =4x

   2

   AC=2x

   (i) sinAcosC+cosAsinC=

   2

   1

   ×

   2

   1

   +

   2

   3

   ×

   2

   3

   =

   4

   1

   +

   4

   3

   =1

   (ii) cosAcosC−sinAsinC=

   2

   3

   ×

   2

   1

   −

   2

   1

   ×

   2

   3

   =

   4

   3

   −

   4

   3

   =0

   solution

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