SSC Selection Post 2023 PYQ — Question 71

The correct answer is Option 2 i.e. $\frac{7}{25}$.

4 tanA = 3

tanA = ${3\over4}={P\over B}$

By Pythagoras' theorem,

H² = B² + P²

here, H  = Hypotaneous, B = Base, P = Perpendicular

H² = 4² + 3²

H² = 16 + 9 = 25

H = 5

⇒ cos²A – sin²A = $({B\over H})^2 - ({P\over H})^2$

⇒ $({4\over 5})^2 - ({3\over 5})^2$

⇒ ${16\over 25} - {9\over 25}$ = $\frac{7}{25}$