And lucky for us, we're allowed to use a calculator, so let's use a calculator to evaluate this. And so let me get my calculator out, and actually let me go see the definitions of r of x and d of x right over here so I can type them in. And what I'm gonna do, and there's a bunch of ways, the more advanced you get with a calculator that might save you some time if you're on the AP test, I'm gonna actually define a function that is r of x minus d of x. So everywhere I see a t, I'm gonna substitute it, I'm gonna use an x instead. And then I could use that later on to integrate it or to solve it in some way. So let's do that. So y one is gonna be 20 times sine of x squared divided by 35, close parentheses, minus, open parentheses, you have negative 0.04 times t to the third power, or sorry, so I'll write times x, x to the third power plus 0.4 times x squared plus 0.96 times x, and then I can close these parentheses.