If $3 \cos ^2 \theta-4 \sin \theta+1=0,0^{\circ}<\theta<90^{\circ}$, then $\tan \theta+\sec \theta=$ ?
Answer & explanation
Correct answer: option 4
We are given that :-
3 cos²θ - 4sinθ + 1 = 0
{ we know, sin²θ + cos²θ = 1 }
3 ( 1 - sin²θ ) - 4sinθ + 1 = 0
3sin²θ + 4sinθ - 4 = 0 = 0
3sin²θ + 6sinθ - 2sinθ - 4 = 0 = 0
3sinθ ( sinθ + 2 ) - 2 ( sinθ + 2 ) = 0
( 3sinθ - 2 ).( sinθ + 2 ) = 0
Either ( 3sinθ - 2 ) = 0 or ( sinθ + 2 ) = 0
If ( sinθ + 2 ) = 0
Then sinθ = -2 is not possible.
So, 3sinθ - 2 = 0
sinθ = \(\frac{2}{3}\)
{ we know, sinA = \(\frac{P}{H}\) }
By using pythagoras theorem,
P² + B² = H²
2² + B² = 3²
B = √5
Now,
tanθ + secθ
= \(\frac{P}{B}\) + \(\frac{H}{B}\)
= \(\frac{2}{√5}\) + \(\frac{3}{√5}\)
= \(\frac{5}{√5}\)
= √5