- Exam
- JEE Main
- Year
- 2021
- Date
- 26 August
- Shift
- Morning Shift
- Subject
- Mathematics
- Chapter
- Continuity and Differentiability
JEE Main 2021 · 26 August · Morning Shift · Mathematics · Continuity and Differentiability
Let a, b ∈ R, b ≠ 0 . Defined a function, f(x) = \ array ll...
Let . Defined a function, f\left(x\right) = \left\{\right)</p><p>Iffx = 010 - ab is equal to
Correct answer
0
Step-by-step solution
We have,
f\left(x\right) = \left\{\right)</p><p>If function is continuous atx = 0LHL = RHL = f\left(0\right)LHL = \lim_{x \to {0}^{-}}\left[asin\dfrac{\pi}{2}\left(x - 1\right)\right]⇒ LHL = \lim_{h \to 0}\left[asin\dfrac{\pi}{2}\left(0 - h - 1\right)\right]⇒ LHL = \lim_{h \to 0}\left[asin\dfrac{\pi}{2}\left(- 1\right)\right]⇒ LHL = - aRHL = \lim_{x \to {0}^{+}}\left(\dfrac{\tan 2x - \sin 2x}{b{x}^{3}}\right)∵ \sin x = x - \dfrac{{x}^{3}}{3 !} + \dfrac{{x}^{5}}{5 !} + \ldots \ldots∵ \tan x = x + \dfrac{{x}^{3}}{3} + \dfrac{2{x}^{5}}{15} + \ldots .RHL = \lim_{x \to {0}^{+}}\left[\dfrac{\dfrac{( 2x{)}^{3}}{3} + \dfrac{( 2x{)}^{3}}{6}}{b{x}^{3}}\right] = \dfrac{\dfrac{8}{3} + \dfrac{8}{6}}{b} = \dfrac{4}{b}f ( 0 ) = asin\left[\dfrac{\pi}{2} ( 0 - 1 )\right] = asin\left(- \dfrac{\pi}{2}\right) = - aRHL = f\left(0\right)⇒ \dfrac{4}{b} = - a ⇒ - ab = 4 ⇒ 10 - ab = 14