limx→11−x2sinπx
=limx→1(1−x)(1+x)sinπx
⇒x→1,x−1→0, let x−1=y⇒y→0
=limy→0(−y)(1+y+1)sinπ(y+1)
=−limy→0y(y+2)sin(πy+π)
=−limy→0y(y+2)−sinπy
=limy→0y(y+2)sinπy2
=limy→0y(y+2)limy→0sin πyπy×πy=2π
limx→11−1xsin π(x−1)