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CBSE Class 12 Math 2013 Solved Paper
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Question : 11 of 29
Marks:
+1,
-0
Show that the function f in A = R - defined as f(x) = is one-one and onto. Hence find
Solution:
f(x) = Let f = f ⇒ = ⇒ 24 - 16 + 18 - 12 = 24 + 18 - 16 - 12 ⇒ 18 + 16 = 18 + 16 ⇒ 34 = 34 Since, is a real number, therefore, for every y in the co-domain of f, there exists a number x in R - such that f(x) = y = Therefore, f(x) is onto. Hence, exists. Now, let y = ⇒ 6xy - 4y = 4x + 3 ⇒ 6xy - 4xx = 4y + 3 ⇒ x (6y - 4) = 4y+ 3 ⇒ x = ⇒ y = int exchanging the variables x and y ⇒ (x) = [put y = x]
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