Practicing Success
Practicing Success
CUET Preparation Today
If $\left(\cos ^2 \theta-1\right)\left(1+\tan ^2 \theta\right)+2 \tan ^2 \theta=1,0^{\circ} < \theta <90^{\circ}$ then $\theta$ is: |
30° 90° 60° 45° |
45° |
( cos²θ - 1 ) .(1 + tan²θ) + 2tan²θ = 1 Using :- sin²θ + cos²θ = 1 & sec²θ - tan²θ = 1 ( - sin²θ ) .(sec²θ) + 2tan²θ = 1 - tan²θ + 2tan²θ = 1 tan²θ = 1 { we know, tan45º = 1 } So, θ = 45º |
