If sec2θ + tan2θ = 4\(\frac{1}{2}\), 0° < θ < 90°, than (cosθ + sinθ) is equal to:
Answer & explanation
Correct answer: option 3
sec2θ + tan2θ = 4\(\frac{1}{2}\)
1+tan2θ + tan2θ = 4\(\frac{1}{2}\)
2tan2θ = \(\frac{9}{2}\) - 1
tan2θ =\(\frac{7}{4}\)
tanθ =\(\frac{\sqrt {7}}{2}\)=\(\frac{P}{B}\)
H=\(\sqrt {(\sqrt {7})^2+(2)^2}\) = √11
⇒ cosθ + sinθ =\(\frac{P+B}{H}\) = \(\frac{\sqrt {7}+2}{ √11}\)