Question

The ratio of the areas of two curves y = cos x and y = cos 2x between x-axis from x = 0 to x = p/3 is

• A. 1 : 2
• B. $2 \sqrt { 3 }$ : 4 – $\sqrt { 3 }$
• C. 1 : 1
• D. None

Answer 1

Answer: (B)

$2 \sqrt { 3 }$ : 4 – $\sqrt { 3 }$

Answer 2

First area = $\int _ { 0 } ^ { \pi / 3 } \cos x d x$ = $[ \sin \mathrm { x } ] _ { 0 } ^ { \pi / 3 }$ z= $\sqrt { 3 } / 2$

second area = +

=$\frac { 1 } { 2 }$ + $\frac { 1 } { 2 }$ – $\frac { \sqrt { 3 } } { 4 }$ = $\frac { 4 - \sqrt { 3 } } { 4 }$