For more cool math videos visit my site at http://mathgotserved.com or http://youtube.com/mathsgotserved good day students in this clip we're going to be reviewing some problems on graph graphs of trig functions lets take a look at this here number one so it says DBA exam amplitude and period of the graph so we have his graph below are makes you examine this closely what kind of a trig function does this look like zero quick review remember your sign function looks like an S and its positive the sign goes up like this that one. if its negative goes in the other direction like this in your are your cosine function looks like a cup so on. Of your cosine function in this positive positive cosine looks like this is registered is positive sign in the red one is negative sign and for this one we see this, orientation that is be positive cosine the positive cosine starts from the maximum okay and the negative cosine starts from the minimum and goes in the opposite direction like that that is the negative cosine okay let's take a look at this graph what does this look like this is looks like the cups started from the maximum to this is a positive cosine function okay Max for the amplitude amplitude is the displacement from the center to the Max or center to the mean okay to the central position the midpoint from the tip to tip from the maximum points to the minimum points this is a central position center and we have to maximum which is where all the peaks Comstock that the maximum displacement from the central position and this is the minimum displacement okay only have our answer Max any now notes that the amplitude is not from the hundred displacement from the main to Max is the displacement from the center to the Max are meant so i can either in it computes this distance from here to here or I can computes this distance from here to hear okay so how many units displacement are there from the center to the maximum or from the center the mean tha will tell us what amplitude is an can clearly see that is for covered it up a little bit so this is for units the case as our amplitude now to calculate hour. There are different ways you can calculator. While complete cycles it. So I we had the maximum here from this maximum to the next Max on this graph that will be our complete. Two can go from Max for maximum to maximum lengths will tell you. Or you can go from minimum to minimum that we will tell you that. Also okay let's do from Max to Max for maximum we can clearly see that the from this Max to this Max these for units and I'm sorry units. We eight pi units so the period is a product right cursor to write it down the amplitude with him before from the center to the maximum is for units in the period from Max to Max is from your do it five is units long to can clearly see that our answer is option letter the okay let's take a look at the number two we asked to sketch the graph of these three functions and down basically say what your similarities and differences are alright so lets start with that with the function number one we have we're going to be graphing three cosine functions semester with the first one but before we do that lets him right down the general form forty equation of trig function so we have why is equal to a cosine bracket X minus H okay okay to that our what we going to be using to generate a graphical dysfunction semester with the first one we have why and we right this function in this format okay the coefficient of cosine is one quite equals one cosine of the function of the X is one so we have bracket one times X minus H is change the H2 A zero six minutes attracting anything from the text exponent zero + zero can have this express so if nothing being added to it you have zero zero here okay now let's determine what the new origin is well graph is going to be centered the origin is going to be zero, zero you can see that our phase shifted zero and a vertical shift the zero I lets figure out what our period is a period is to pi over b to buy ever be in this problem be equals one so we have two pi equals our period In that tells is that for checks is going to be equal to find okay in denominator calibration where using degrees of one or I this in degrees we can have four takes equals pies one eighty-two two pieties three hundred and sixty degrees I so i think at thing that's enough information to graph this function oh yeah we also need and their amplitude our amplitude is a amplitude is the absolute value of a celebrity computer the absolute value of one which equals right now lets out go ahead and graph the function so we are starting from zero zero in our amplitude is one so graphical one here.mil function can go in any political as low as one okay so for chicks is equal to three hundred and sixty
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