AP Calculus AB Unit 7.3: Slope Fields
Practice AP Calculus Unit 7.3 questions on sketching solution curves through slope fields and estimating differential-equation behavior.
- Syllabus
- Effective Fall 2025
- Course
- AP Calculus AB
Practice AP Calculus Unit 7.3 questions on sketching solution curves through slope fields and estimating differential-equation behavior.
The depth of seawater at a location can be modeled by the function H that satisfies the differential equation dtdH=21(H−1)cos(2t), where H(t) is measured in feet and t is measured in hours after noon ( t=0 ). It is known that H(0)=4.
A portion of the slope field for the differential equation is provided. Sketch the solution curve, y=H(t), through the point (0, 4).

Solution curve 1 point
Scoring notes:
- The solution curve must pass through the point (0,4), extend to at least t=4.5, and have no
obvious conflicts with the given slope lines.
- Only portions of the solution curve within the given slope field are considered.
Total for part (a)
1 point
(b) For 0<t<5, it can be shown that H(t)>1. Find the value of t, for 0<t<5, at which H has a
critical point. Determine whether the critical point corresponds to a relative minimum, a relative
maximum, or neither a relative minimum nor a relative maximum of the depth of seawater at the
location. Justify your answer.