Set 2: Test each of the following equations to show that they are scale invariant. Find their general solutions (It is not necessary to do the antiderivatives. Note that not all these equations are scale invariant in the simplest sense, i.e., n=1). 1. xy' ty /x = xey/2 2. (x2 + 32) dy + (32 - a2) dac= 0 3. (x + y?) dy +ydx =0 4. (y + 2) dy - 23 da = xysin (x /y) dx