SYDNEY BOYS - Multiple Choice Question (1 Viewer)

[hscwav2012]

SBHS 2012 Trial - MC Q7

Consider the graph of f(x) = (sinx)^3
For -pi < x < 2pi
The area bounded by the graph of f(x) could be found by evaluating:

Note - limits for all option are from -1 to 1
A (1-u^2) du

B 3(1-u^2) du

C -(1-u^2) du

D -3(1-u^2) du

Their solution says the answer is B? Where did the 3 come from?

 

[SpiralFlex]

Dead pic mate

 

[LoveHateSchool]

Which SBHS MC? No pic. But Q number?

Haha just saw this was on MX2 sorry. *Bows out*

 

[RealiseNothing]

C

 

[zeebobDD]

B

 

[asianese]

E

 

[hscwav2012]

Is the solution answer correct?

 

[RealiseNothing]

Is the solution answer correct?

Ahhh I just re-read the question.

It should be C, but the question asks for the area bounded by the graph, so you multiply by 3 and get rid of the negative as the curve between and is 3 sets of equal areas (and when you evaluate the integral you are only finding the area of one of these areas as the other two cancel out).

 

[math man]

b is correct, just draw the curve

 

[LTEHSC]

b is correct, just draw the curve

Yes, the correct answer is B.
Please see worked solution in the attachement.