Vertical Strips (dx) vs Horizontal Strips (dy):
- Vertical strips work best when curves are given as y = f(x) and don't require splitting
- Horizontal strips work best for curves like = 4ax or x = g(y), and when vertical strips would require multiple integrals
- Example: area between x = and x = 2- needs one integral with dy but two with dx
Direct Integration vs Symmetry:
- Direct integration is always valid but may involve tedious computation
- Symmetry (even/odd/periodic) can reduce work by half or more
- Example: ellipse area with 4-fold symmetry needs only the first quadrant integral
Cartesian vs Parametric vs Polar:
- Cartesian is the default for most JEE problems
- Parametric is needed for curves like cycloids or when x and y are given in terms of a parameter t
- Polar is needed for cardioids, rose curves, and spirals
Signed Integral vs Geometric Area:
- Signed integral: direct output of the definite integral, can be zero or negative
- Geometric area: always positive, requires splitting at zeros and taking absolute values
- The problem statement determines which to compute: "area bounded by" means geometric area
Formula Shortcuts vs Full Integration:
- Standard results (8/3 for parabola, |a|(beta-alpha)^3/6 for quadratic) save time
- Full integration is needed when standard results don't apply
- In JEE, using memorized formulas can save 2-3 minutes per problem