y=sinx

Sinx is a function.its mean for every x(x=1,2,3,...n) we get one value .otherwise it is called relation.concepts of one-one or many-one onto function.

To find sin–x graph through sinx graph.

Rotate this figure 90°anticlock wise.

After rotation negative numbers are placed right side of zero .this is not standard form.But its mirror image form a standard form.

This graph show relation between x and y .not a fuction because this not follow one-one or many-one rule.

So we reduce the graph to make one -one function.