Expressing x in Terms of y, to Find the Range of a Function
The number of...
Question
The number of integers in the range of f(x)=sec−1(9x2+6x−1) is
A
1
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B
2
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C
3
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D
4
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Solution
The correct option is C3 Let t=9x2+6x−1⇒t=(3x+1)2−2 ⇒t≥−2 For f(x) to be defined, t∈[−2,−1]∪[1,∞) ⇒sec−1(t)∈[0,π2)∪[2π3,π] Integers in the range of f(x) are 0,1,3