Key to Math 336 Test 1 of Summer 2008


1. Direct substitution (do NOT solve eq)

2. e^{3x/5} & e^{-2x}

3. 1 or 1 +1/(x^{-2}+C)^{1/5}

4. e^x sin y +x y -x^5 +y^3 =C

5. The IVP has a solution if a not= -5; and
   it has a unique solution if a not= -5 & b not= 0.

6. y(x) =-x ln(C -ln(x^2))

7. 897 (kgs)