Πεψενθε 

`and`(y = `+`(`*`(5, `*`(ln(`+`(x, 5)))), `-`(`*`(5, `*`(x)))), `+`(`*`(5, `*`(ln(`+`(x, 5)))), `-`(`*`(5, `*`(x)))) = `*`(5, `+`(ln(`+`(x, 5)), `-`(x)))) 

`and`(diff(y(x), x) = `*`(5, `+`(`/`(1, `*`(`+`(x, 5))), `-`(1))), `and`(`*`(5, `+`(`/`(1, `*`(`+`(x, 5))), `-`(1))) = `+`(`/`(`*`(5, `*`(`+`(`+`(1, `-`(x)), -5))), `*`(`+`(x, 5)))), `+`(`/`(`*`(5, `*... 

`and`(y(-4) = y[max], y[max] = 20) 

maximize(`+`(ln(`*`(`^`(`+`(x, 5), 5))), `-`(`*`(5, `*`(x)))), x = -5 .. 5) 

20 (33.2.1)
 

plot(`+`(`-`(`/`(`*`(5, `*`(`+`(x, 4))), `*`(`+`(x, 5))))), x = -5 .. 10, y = -10 .. 10, filled = true, color = gray) 

Plot_2d