In triangle ABC, right-angled at B, if 
find the value of:
(i) Sin A Cos C + Cos A Sin C
(ii) Cos A Cos C – Sin A Sin C
tan A = 
= 
If BC is k, then AB will be, where k is a positive integer
In ΔABC,
AC2 = AB2 + BC2
= (
)2 + (k)2
= 3k2 + k2 = 4k2
AC = 2k
Sin A = 
= 
= 
Cos A = 
= 
= 
Sin C = 
= 
= 
Cos C = 
= 
= 
(i) sin A cos C + cos A sin C
= (
(
) + (
= 
= 
(ii) cos A cos C - sin A sin C
= (
) (
) – (
) (
)
= 
= 0
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