Correct option is A
Given:
13sinA−12=0
5sinA+12cosA+tan2A−(sec2A−1)=?
Concept Used:
sin2A+cos2A=1
tanA=cosAsinA
sec2A−1=tan2A
Solution:
= 13sinA−12=0
=>13sinA=12
=>sinA=1312
Using the Pythagorean identity , sin2A+cos2A=1,
(1312)2+cos2A=1 =>169144+cos2A=1 =>cos2A=16925
Since A lies in the second quadrant,(cosA=−135)
= 5sinA+12cosA+tan2A−(sec2A−1)
= 5sinA+12cosA+tan2A−tan2A
= 5sinA+12cosA
Now, substitute the values of sinA and cosA from above
= 5×1312+12×(−135)
= 1360−1360=0
Thus, the value of the expression is 0.