1. Find a function whose square plus the square of its derivative is 1. (5 pts) dy 2. Can any solution of dr v(4) = -3 cross the -axis? Do you think that += 1 is an dy implicit solution of the IVP (1) 0? (10 pts) da 3. Construct a lincar first-order differential equation for which all nonconstant solutions approach the horizontal asymptote as y 4. In determining integrating factors of linear DEs, the constant of integration in the evaluation of SP(2) dr. Explain why using SP(a) dar + c has no effect on the solution. (10 pts) 4 as r- 0. (5 pts)