JEE Main 2022 · 29 June · Evening Shift · Mathematics · Limits
D. π2{\pi}^{2}π2
Given, limx→1(x2−1)sin2(\pix)x4−2x3+2x−1\lim_{x \to 1}\dfrac{\left({x}^{2} - 1\right)\sin^{2}\left(\pix\right)}{{x}^{4} - 2{x}^{3} + 2x - 1}limx→1x4−2x3+2x−1(x2−1)sin2(\pix)
=limx→1(x2−1)sin2(\pix)(x2−1)(x2−2x+1)= \lim_{x \to 1}\dfrac{\left({x}^{2} - 1\right)\sin^{2}\left(\pix\right)}{\left({x}^{2} - 1\right)\left({x}^{2} - 2x + 1\right)}=limx→1(x2−1)(x2−2x+1)(x2−1)sin2(\pix)
=limh→0sin2(π(1+h))(1+h−1)2= \lim_{h \to 0}\dfrac{\sin^{2}\left(\pi\left(1 + h\right)\right)}{{\left(1 + h - 1\right)}^{2}}=limh→0(1+h−1)2sin2(π(1+h))
=limh→0sin2\pihh2=limh→0(sin\pih\pih)2π2=π2= \lim_{h \to 0}\dfrac{\sin^{2}\pih}{{h}^{2}} = \lim_{h \to 0}{\left(\dfrac{sin\pih}{\pih}\right)}^{2}{\pi}^{2} = {\pi}^{2}=limh→0h2sin2\pih=limh→0(\pihsin\pih)2π2=π2