Concept:Use the trigonometric identity sec2θ=1+tan2θ to solve for θ.Explanation:Given: sec2θ+tan2θ=3.Replace sec2θ with 1+tan2θ.So, 1+tan2θ+tan2θ=3.This simplifies to 1+2tan2θ=3.Subtract 1 from both sides: 2tan2θ=2.Divide both sides by 2: tan2θ=1.Take the square root: tanθ=±1.In the given range, tanθ=1 when θ=45∘.Therefore, θ=45∘.Answer:C. 45∘