limx→π√5+cos x−2(π−x)2
limx→π√5+cos x−2(π−x)2
⇒x→π,thenπ−x→0,letπ−x=y
=limy→0√5+cos(π−y)−2y2
=limy→0√5−cos y−2y2
=limy→0(√5−cos y)−2y2×(√5−cos y+2)(√5−cos y+2)
=limy→0(5−cos y−4)(√5−cos y+2)
=limy→02sin2y2(√5−cos y+2)
=2×(limy→0sin y2y2)2×141limy→0(√(5−cos y)+2)
=2×14×1√4+2=2×14×14
=18