I know you just threw together a random formula for illustrative purposes, but I was curious: https://www.wolframalpha.com/input/?i=maximize+%7B+%28e%5E%28.1x%

I know you just threw together a random formula for illustrative purposes, but I was curious: https://www.wolframalpha.com/input/?i=maximize+%7B+%28e%5E%28.1x%5E2+%2B+.4x%29+%2B+5cos%28pi+*+x%29+-+sqrt%28x%5E2+%2B+1%29+-+4%29+%2F+x+%7D+for+3+%3C+x+%3C+5 https://www.wolframalpha.com/input/?i=maximize+%7B+%28e%5E%2... -> You can find C by imposing equality for x = 5.