Question

The ratio of the areas between the curves y = cos x and

y = cos 2x and x-axis from x = 0 to x = $\frac { \pi } { 3 }$ is

• A. 1 : 3
• B. 2 : 1
• C. $\sqrt { 3 }$ : 1
• D. None of these

Answer 1

Answer: (B)

2 : 1

Answer 2

A₁ = $\int _ { 0 } ^ { \pi / 3 } \cos x d x = \frac { \sqrt { 3 } } { 2 }$

A₂ = $\int _ { 0 } ^ { \pi / 2 } \cos 2 x d x = \frac { \sqrt { 3 } } { 4 }$

\ $\frac { \mathrm { A } _ { 1 } } { \mathrm {~A} _ { 2 } } = \frac { 2 } { 1 }$