If 0 ≤ θ ≤ /2 and sec2θ + tan2θ = 7, then θ is

Answer: Option B

sec²θ + tan²θ = 7
1 + tan²θ + tan²θ = 7
2tan²θ = 7 - 1 = 6
tan²θ = 3
tanθ = √3 = tan 60°
$$\begin{array}{rl}& \because 180^{\circ }=\pi \text{ radian}\\ & \therefore 60^{\circ }=\frac{\pi }{180}\times 60=\frac{\pi }{3}\text{ radian}\end{array}$$