CUET Preparation Today
If tan3θ.tan7θ= 1, where 7θ is an acute angle, then find the value of cot15θ. |
1 -1 -$\sqrt{3}$ $\sqrt{3}$ |
-1 |
tan3θ.tan7θ= 1 tan3θ = $\frac{1}{tan7θ}$ tan3θ = cot7θ tan3θ = tan(90 - 7θ) Thus, 3θ = 90 - 7θ 10θ = 90 or θ = 9 cot15θ = cot135 = -1 |
