TrigSubstitution.mws E.G. Find the area of a circle of radius 2 units. Trigonometric Substitutions first form: Int(x^3*sqrt(9-x^2),x); second form: Int(1/(x*sqrt(x^2+3)),x); third form: find the area under y = sqrt(9*x^2-4)/x; above [2/3, 2*sqrt(2)/3]; . Two that look different. #37 page 489