If 5sin2 θ = 3(1 + cosθ), 0° < θ < 90°, then the value of cosecθ + cotθ is : |
$\frac{4}{\sqrt{21}}$ $\sqrt{\frac{3}{7}}$ $\frac{5}{\sqrt{21}}$ $\sqrt{\frac{7}{3}}$ |
$\sqrt{\frac{7}{3}}$ |
5sin2 θ = 3(1 + cosθ) { sin2 θ + cos2 θ = 1 } 5 ( 1 - cos2 θ) = 3(1 + cosθ) 5 ( 1 - cos θ) = 3 cos θ = \(\frac{2}{5}\) By using pythagoras theorem , P2 + B2 = H2 P2 + 22 = 52 P = \(\sqrt {21 }\) ATQ, cosecθ + cotθ = \(\frac{5}{√21}\) + \(\frac{2}{√21}\) = \(\frac{7}{√21}\) = \(\frac{√7}{√3}\) |