benji_10
Member
- Joined
- Mar 3, 2010
- Messages
- 104
- Gender
- Male
- HSC
- 2011
a) A flag pole 9m high stands on top of a support. The top if the support is 16m above the eye-level of the observer. If the flagpole subtends an angle, theta, at the eye of the observer who is standing x metres away from the support: It looks like this: http://i51.tinypic.com/28lb7ly.png
i) Show that theta = arctan(25/x) - arctan(16/x) ----> arctan is inverse tan
ii) Find that value of x which makes theta a maximum.
iii) Show that the max value of theta is arctan(9/40)
I already got part i). It's just parts ii) and iii) that bugs me. Not sure whether to use calculus because you can't differentiate arctan when the x term is on the bottom.
Thanks guys!
i) Show that theta = arctan(25/x) - arctan(16/x) ----> arctan is inverse tan
ii) Find that value of x which makes theta a maximum.
iii) Show that the max value of theta is arctan(9/40)
I already got part i). It's just parts ii) and iii) that bugs me. Not sure whether to use calculus because you can't differentiate arctan when the x term is on the bottom.
Thanks guys!