# Math Help - r formula visualization

1. Originally Posted by arccos
Well I already looked at the answer so i would pick 1-sqrt(5)(-1).So the point here is to notice that only by equating it to -1 can we obtain all positive values in the maximum value?
and if so, for the expression to be maximum, there must only be positive values?
I don't understand what you just said. The expression is maximum when the sine is minimum.

2. Originally Posted by arccos
Of course, you can plot the graph and take its maximum value from it but it really isn't necessary.

1 - sqrt(5)sin (x+26.57)

What we can do now is to decide for sin (x+26.57) to be maximum or minimum and that's by equating it to 1 and -1 because the maximum or minimum depends on sin (x+26.57). There is nothing else we can alter in the expression other than that.