Since #cos(x-\pi/2)=sin(x)#, we can simplify the expression into
#4sin(x)+1#
If you know the graph of #sin(x)#, then you have simply multiplied the function by #4#, and then added #1#.
Multiplying by four results in a vertical stretch. In fact, where #sin(x)# is zero, #4sin(x)# is still zero. On the other hand, the maxima and minima (which of course are #1# and #-1#), now become #4# and #-4#. All the intermediate points must follow accordingly, and so, the function result stretched.
When you add #1#, you are not associating anymore #y=f(x)#, but #y=f(x)+1#. This means that you have added one unit to the #y# coordinate, which means that you translated the graph one unit upwards. Here are the graph of the changes:
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The fact that #cos(x-pi/2)=sin(x)#, here
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The vertical stretch from #sin(x)# to #4sin(x)#, here
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The upward shift from #4sin(x)# to #4sin(x)+1#, here
