OK, when doing this problem, the first thing we need to do is we need to make sure our graphing calculator is in the right settings. So if we go to the home key, the house over here, and then #5 we want to look at document settings. And we need the angle to be in degree. And I'm going to make it default so that it's true for everything, whether I'm in the scratch pad or in the current document. I'm going to go ahead and just make a new document. No, I don't want to really save anything. And I'm going to add a calculator. So I need all that in just a moment to solve this problem. So when we look at this problem, it gives us lots of information and it says we have this cotangent Theta equaling 2X over two y + g * t ^2, where Theta is the angle of the elevation of the launcher G's acceleration. So X up here, by the way, the projectile fired into the first quadrant from the origin will pass through the point XY. So X is going to be how far it goes and Y is going to be the height. So an artillery menace fire an enemy bunker located 2600 feet up the side, That's our Y because it's up the side that is 6300 and 6350 feet away. So this is our X because it's away, it's out in front. He fires around exactly 2.73 seconds later. So that's our time. So we're going to have our cotangent Theta equaling 2 times our 6350 / 2 times our 2600 plus our G. And it's given here as our gravity is 32.2 times our time 2.73 ^2. So when we put this into our calculator, we're going to go into the calculator and we're going to do, we can do it lots of different ways. We could type in cosine inverse and just come back and arrow back and change the S to AT and that'll make it cotangent inverse. And so when I type this in, I'm going to have a parenthesis to tell me that we're up in the top 2 * 6350 close my parenthesis divided by. I'm going to put another parenthesis to say I'm all in the denominator 2 * 2600 + 32.2 * 2.73 and there's a square key right over here. I'm going to close my parentheses. I'm going to do a control enter because I want an approximate angle. So I'm going to get 23.1876 blah blah blah. I believe it's said to round to 1 decimal, so 23.2 because that eight was bigger than 55 or bigger. So if we go back to the problem, we got 23.2 says don't round the answer to the final. So I typed it all in just like it was. The second part says if the angle of elevation is given by secant Theta V naughty t / X, where V naughty is the muzzle find V naughty. Well, we know secant. I'm going to actually use this whole angle in a minute, but we could probably get away with using the approximate, but I'm going to use the actual angle. Then we're going to multiply it by X because we're going to cross multiply and our X remember was that 6350? And then we're going to divide it by T and our T was 2.73 to get the V not all by itself. So if we just looked at the equation, our first thing would be to multiply each side by X. And then if we want to get our V not by itself, we're then going to divide each side by T. So when I put this into the calculator, let's go back to my calculator. I'm going to put in X. So 635 O times secant is just one divided by cosine. So 1 divided by cosine. Now I'm actually going to go up here and grab that angle. If I just arrow up one time, see how it's Gray, I'm going to hit enter and I'm going to close that parenthesis and then I'm going to have divided by the time which was 2.73. Once again, I'm going to hit control enter and I get 253 O .413, yadda yadda. So if we go back to the problem 253 O .41 because it wanted it rounded to 1 decimal place.