You can obtain the graph of the function y=-2sinx-1 from the graph of the function y=sinx making such transformations:
1. <span>the multiplication by -2 increases y value twice and then symmetrically reflects the graph y=2sinx about the x-axis;</span>
2. adding -1 to the <span>y=-2sinx you translate the graph 1 unit down.
</span><span>
</span><span>On the added picture black line is a graph of y=sinx and red line is a graph of y=-2sinx-1.</span>
Check:
1. When x=0, y=-2sin0-1=-1;
2. When
, then 
.
1. <span>the multiplication by -2 increases y value twice and then symmetrically reflects the graph y=2sinx about the x-axis;</span>
2. adding -1 to the <span>y=-2sinx you translate the graph 1 unit down.
</span><span>
</span><span>On the added picture black line is a graph of y=sinx and red line is a graph of y=-2sinx-1.</span>
Check:
1. When x=0, y=-2sin0-1=-1;
2. When