Question

solve this............

Answer 1

Given:AC-AB=1cm---------(i)
and BC=7cm.

In rt. angled triangle ABC, rt. angled at B:-
(BC)sq.=(AC)sq.-(AB) sq. -------{BY PYTHAGORAS THEOREM}
»(BC) sq. =(AC-AB) (AC+AB)-------[because (a) sq. - (b) sq. = (a-b)(a+b)]
»(7)sq.=(1)(AC+AB)
»AC+AB=49------(ii)

adding (i) and (ii) we get:-
2AC=50
»AC=50/2
»AC=25cm.

subtracting (i) from (ii) we get:-
2AB=48
»AB=48/2
»AB=24cm.

SO,
sinA=BC/AC=7/25

cosA=AB/AC=24/25

therefore, SINA+COSA=7/25+24/25=21/25.

HOPE IT HELPS YOU.