Find the Domain square root of (sin(x))/x
Problem
Solution
Identify the constraints for the domain of the function. For a square root function
√(,ƒ(x)) the expression inside must be non-negative:sin(x)/x≥0 Additionally, the denominator cannot be zero, sox≠0 Analyze the behavior of the function at the point of discontinuity
x=0 Since(lim_x→0)(sin(x)/x)=1 which is greater than zero, the function is defined in a neighborhood aroundx=0 excludingx=0 itself.Determine the intervals where the numerator and denominator have the same sign. The expression
sin(x)/x is positive whensin(x) andx are both positive or both negative.Solve for the case where
x>0 We requiresin(x)≥0 This occurs on the intervals(0,π]∪[2*π,3*π]∪[4*π,5*π]… which can be written asx∈[2*k*π,(2*k+1)*π] fork∈{0,1,2,…} excludingx=0 Solve for the case where
x<0 We requiresin(x)≤0 This occurs on the intervals[−π,0)∪[−3*π,−2*π]∪[−5*π,−4*π]… which can be written asx∈[(2*k−1)*π,2*k*π] fork∈{0,−1,−2,…} excludingx=0 Combine the intervals into a general form. The condition
sin(x)/x≥0 is satisfied whenx∈(⋃_k∈ℤ∖{0}^)(2*k*π,(2*k+1)*π) if we consider the sign ofx relative to the quadrants of the sine function. Specifically, the domain is the union of(−π,0)∪(0,π] and all intervals wherex andsin(x) share a sign.
Final Answer
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