Proving whether a function is one one or onto is totally dependent on the domain and codomain of the function. I assume that domain and codomain are the set of all Real numbers.
Now consider x= 0° & 180 °, you will get the same y value =>Hence function is not one one
For any x; 5 <=y <=7
Therefore, there will be many values in codomain set, for which there is not any preimage in the domain set. Hence function is not onto function.
