Math problem where graphing calculator may slow you down - part II.

[CR Haeger]

Hello - here is a problem that should be fairly easily solvable by hand and with a trig table:

Assume f(x) = max(sin(x), cos(x)) using radians. If the area under the curve f(x) = 4.0 and the lower limit of x = 0.0, what is the upper limit of integration?

What do your machines and/or brains come up with?

Note - I got this to work on the HP Prime using the AREA() function in Function APP, but had problems using solve() or fsolve() properly. Num-Solv on a TI36x had to think about this a looong time.