So here's the deal. I'll put the logarithm bases into (). Solve log(cosx)sinx+ log(sinx)cosx=2.
Whew, the bases are functions of x? That's pretty gnarly. Mixing logs and trig functions . . . will probably end up with complex numbers. This will take some work.
It should be done without complex numbers.
My best guess is pi/4.
There may be other solutions, but I know that works.
Want to know how I did it?
Sure.
I took the simplest case in which \[\log_{\cos x}(\sin x) =\log_{\sin x}(\cos x) = 1.\] A logarithm equals 1 when the base and what it is operating on are equal. sin x = cos x at pi/4.
That's true.
It'll take a little more doing to see if there are other solutions.
e.g. log_{cos x}(sin x) could be 1.5 and log_{sin x}(cos x) could be 0.5 and so on.
That's also true.
I think I can continue from now on. You gave me the ideas I needed. Thank you very much!
Thank you. That was a fun one!
Join our real-time social learning platform and learn together with your friends!