Why does Gottfried Leibniz not get equal recognition for deriving Calculus?
I’m really not sure exactly why this is; in fact, most of the text books I’ve seen have recognized that both invented it independently, and mention the different situations when Leibniz’s notation is preferable to Newton’s and vice versa. Perhaps a reason would be that Newton was English, and the textbooks you read are written in english, or even published by British companies, and so would prefer to give credit to a British anglophone than to Leibniz. On the other hand, I wouldn’t be surprised if some German textbooks give credit solely to Leibniz, while whitewashing over Newton’s contributions.