CBSE Class 12 Sample Paper for 2023 Boards

Class 12
Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

## Find the intervals in which the function is strictly increasing/strictly decreasing

### Transcript

Question 36 (iii) - Choice 1 Find the intervals in which the function is strictly increasing/strictly decreasingNow, our function đ(đĽ) = â0.1đĽ^2 + đđĽ + 98 Putting m = 1.2 đ(đĽ) = â0.1đĽ^2 + 1.2đĽ + 98 đ(đĽ) = ăâđĽă^2/10+12đĽ/10+98 đ(đĽ) = đ/đđ(âđ^đ+đđđ+đđđ) Now, checking if f(x) is increasing Finding fâ(đ) đ(đĽ) = đ/đđ(âđ^đ+đđđ+đđđ) Differentiating wwr.t x đâ (đĽ) =1/10(â2đĽ+12) Putting fâ(đ) = 0 đ/đđ (âđđ+đđ)=đ â2đĽ + 12 = 0 â2đĽ = â12 đĽ = (â12)/(â2) đ =đ Plotting points on number line Since we are given interval [đ , đđ] Hence, f is strictly increasing in [đ, đ) f is strictly decreasing in (đ,đđ]