Question

Evaluate the integral? : ∫1sinxdx

Answer 1

Ur answer is (-cos x+c) because integration of sin x is -cos x

Answer 2

1/sinx = cosecx

multiply cosecx by (cotx + cosecx) / (cotx +cosecx)

=cosecx(cotx + cosecx) / (cotx +cosecx)

Now you have function and derivative: ( d/dx(cotx + cosecx) = -cosec^2x - cosecx.cotx )

INT(cosecx(cotx + cosecx) / (cotx +cosecx))

= -ln(cosecx + cotx)