The Student Room Group

Maths help

can anyone explain to me how to calculate this (on attachment)
Original post by tc32
can anyone explain to me how to calculate this (on attachment)


Integrate it using substitution given.
Reply 2
Original post by RDKGames
Integrate it using substitution given.


what about the second part?
Original post by tc32
what about the second part?


It's a modulus of the function; so everything in the negative y flips over to positive y. Imagine 40 of those 'humps' (with area A) going across and you can find out where the last one hits the x-axis, that would be your kπk\pi
Reply 4
Sub kpi and zero into integral and equate it to 40*your A?
Original post by TSRPAV
Sub kpi and zero into integral and equate it to 40*your A?


No need to mess around with any integrals, to be honest, that would just take longer. Observe the pattern of the modulus. If the boundary for A is between 0 and π4\frac{\pi}{4}, then obviously the boundary for 40A would be between 0 and 40π440\cdot \frac{\pi}{4}
Reply 6
Original post by RDKGames
It's a modulus of the function; so everything in the negative y flips over to positive y. Imagine 40 of those 'humps' (with area A) going across and you can find out where the last one hits the x-axis, that would be your kπk\pi


I didn't notice that. Thanks for the help, its a whole lot clearer now.

Quick Reply