Using the Pythagorean identity: sin^2(\theta) + cos^2(\theta) = 1
(1/10)^2 + cos^2(\theta) = 1
1/100 + cos^2(\theta) = 1
cos^2(\theta) = 1 - 1/100
cos^2(\theta) = 99/100
cos(\theta) = ±√(99/100)
Since \theta is in the first quadrant (0<\theta <π/2), cos(\theta) is
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