evaluate sin x - sin a / x-a?

 then here's d solutn;

we know that ->sinx-sina=2cos(x+a/2)sin (x-a/2)

so,the questn becomes  :

lim x tends to a   2cos(x+a/2) sin(x-a/2)/(x-a)

now multiply 1/2 in both numerator & denominatr. & separate the limits.

then we get, lim x tends to a   cos(x+a/2) * lim x tends to a   sin(x-a/2)/x-a/2

we know lim x tends to a   sin(x-a/2)/x-a/2=1

so, lim x tends to a   cos(x+a/2)

put value of a

cos 2a/2

cos a

hope dis helps!!!!!

:)