Find dy/dt, given that y=x^2+4x and x=cos(3t). 11/8/2013 | Sun from Los Angeles, CA | 1 Answer | 0 Votes Mark favorite Subscribe Comment
dy/dt =(dy/dx)(dx/dt) = (2x+4)(-sin(3t))(3) = -6(cos(3t)+2)(sin(3t)) or y = cos^2(3t)+4cos(3t) dy/dt = 2cos(3t)(-sin(3t)(3) - 12sin(3t) = -6(cos(3t)+2)(sin(3t)) 11/9/2013 | Robert J. Best answer Comment