If 6tanA (tanA+1) = 5-tanA, Given thaht 0 < A < what is the value of (sinA + cosA)?
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Correct answer: D
Explanation
The correct answer is option 4 i.e.
Formula used:
When a quadratic equation is given i.e. ax2 + bx + c = 0
The roots of the equation are given as:
----- (1)
Calculations:
⇒ 6tanA(tanA + 1) = 5 - tanA
⇒ 6tan2A + 6tanA = 5 - tanA
⇒ 6tan2A + 7tanA - 5 = 0
Using equation (1), we get
tanA = 1/2, -5/3
We will take the value of tanA = 1/2 = perpendicular/base
Now using Pythagoras theorem
Hypotenuse2 = (√4 + 1)
Hypotenuse = √5
cosA = 2/√5 and sinA = 1/√5
(sinA + cosA) = 2/√5 + 1/√5 = 3/√5