fx-9750giii vs fx-CG50

[lrdheat]

...checking the 9750giii some more vs the CG50, using SolveN on d/dx(cos x/(2+sin x) for a 1 to 7 range on the CG50 brings up a solution of 7pi/6. Regardless of how tight a domain I try on the 9750giii, I cannot get it to find a solution. Solve (as opposed to SolveN) does find a solution on the 9750giii over a wide domain (1 to 7) in a decimal approximation. I wonder what causes the different behavior.