21) y = sec (csc 4x5) A) = 20x4sec (csc 4x5)tan (csc 4x5)csc 4x5cot 4x dy B) = 20x4sec2 (csc 4x5)csc 4x5cot 4x dx dy = 20x4sec (csc 4x5)cot (csc 4x5)csc 4x5cot 4x dx dy = 20x4sec (csc 4x5)tan (csc 4x5)csc 4x5cot 4x5 dx csc 4x 22) (4x2 + dy 4xcsc 4x5 (20x5cot 4x5 15x3cot 4x5 6) dx 4x2 + 3 dy 4xcsc 4x5 (20x5cot 4x5 15x3cot 4x5 6) dx (4x2 + dy 4x(4x2 + 4x5 15x3cot 4x5 6) dx csc 4x dy D) = 4xcsc 4x5 (4x2 + 4x5 15x3cot 4x5 6) dx 23) csc 4x3 (2x5 + A) = 4x3cot 4x3 + + 15x2) dx dy B) = 4x3 (2x5 +3) dy C) = 4x2csc 4x3 (2x5 + 6x5cot 4.r3 9cot 4x3) dx D) = 480x6csc 4x3cot 4x3 (2x5 + 3)