## kaylalynn Group Title Which of the following functions is not a sinusoid? y = sin x y= Sqrtx y = cos x None of the above are sinusoids. one year ago one year ago

1. ghazi Group Title

definitely $\sqrt x$ is not a sinusoid , it doesn't vary as a sine wave or a cosine wave

2. kaylalynn Group Title

thats what i was thinkging thanks!!

3. ghazi Group Title

|dw:1369863782806:dw|

4. kaylalynn Group Title

btw does a sinusoid have to go below the x axis??

5. ghazi Group Title

no, sinusoid wave are those which show a smooth repetitive variation or oscillation , like a sine wave or a cosine wave , it doesn't have to go below x axis, if you shift the origin up with respect to the original origin you wont have it below x axis, its just a general trend

6. ghazi Group Title

|dw:1369863941221:dw| O new is the new origin

7. reemii Group Title

I would say yes (it has to go below), since I take as definition that a sinusoid is a function of the form $$\lambda \sin(\alpha x + \phi)$$, with $$\lambda, \alpha, \phi\in\mathbb R$$. But you allow a vertical translation in your definition the answer is yes..

8. kaylalynn Group Title

how bout this then??

9. reemii Group Title

you have to find in your definition in your course. (wikipedia says that the general form allows for a vertical shift). If your definition is the general definition, then there are two sinusoid curves on this picture.