To show increasing/decreasing in whole domain
To show increasing/decreasing in whole domain
Last updated at Dec. 16, 2024 by Teachoo
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Example 7 (Method 1) Show that the function given by f (đĽ) = 7đĽ â 3 is strictly increasing on R.f(đĽ) = 7đĽ â 3 Finding fâ(đ) fâ(x) = (7x â 3)â fâ(x) = 7 Since fâ(đ) > 0 Hence, f is strictly increasing on R Example 7 (Method 2 ) Show that the function given by f (x) = 7x â 3 is strictly increasing on R. Let đĽ1 and đĽ2 be real numbers Such that đđ < đ2 Multiplying both sides by 7 7đĽ1 < 7đĽ2 Subtracting both sides by 3 7đĽ1 â 3 < 7đĽ2 â 3 f (đđ) < f ( đ2) Hence, when x1 < x2 , f(x1) < f(x2) Thus, f(x) is strictly increasing on R.