I have two points. (-1,-5) is one of the minimum points and (3.5,-4) is one of the maximum points. I'm not sure if this is a sin or a cosine function. Please write the equation to this problem. 

 Sep 13, 2019

.I literally just watched a video on how to do this, this is a learning process for me too smiley

I am assuming that you learned the trig vocabulary for this as you asking these problems



Lets first do a cosine graph cuz its easier


This is the base equation for a cosine graph:






So first find the amplitude, which is the height of the waves of the graph. (using y-values)









Now we have the "A" value





Ok now we have to find the period

We first find the positive difference of the x values to find the horizontal distance.




Then we double what we got




Then we solve for the b-value




Now we have



Now we have to find the phase shift (h-value)


Since it has shifted -1,                          ( coordinate (-1, -5) tells us that. )


We now have:



Now we have to find the vertical shift (c-value)

Formula for that is 







So the equation of the sinusoidal graph is




This is the cosine graph.


This is the video I learned from, if you want to find the sine graph, follow the steps in the video.

 Sep 14, 2019

I appreciate your answer. Thank you so much CalculatorUser!!!

hellospeedmind  Sep 14, 2019

Your welcome!

CalculatorUser  Sep 14, 2019

I was on Khan Academy. I typed in the answer, and it turns out that y=0.5cos((2π/9)​x−(7π/9​))−4.5 is the answer. 

hellospeedmind  Sep 14, 2019

did it tell you why the h-value was wrong?

CalculatorUser  Sep 14, 2019

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