Integral of sqrt(81-x^2)dx using the substitution of x=9sint

3382-299=3383- ? fill in the blank?

If sin(x) = 0 and cos(x) = 1, what is tan(x)?

Amass weighing 16 pounds stretches a spring 8/3 feet. the mass is initially released from rest from a point 2 feet below the equilibrium position, and the subsequent motion takes place in a medium that offers a damping force that is numerically equal to 1/2 the instantaneous velocity. find the equation of motion if the mass is driven by an external force equal to f(t)=cos(2t).