1. x2 - yz = 8 d d dy (x2 - y2) 8 dx d dx (x2 - yz ) = _ d dx (8) d dx (x2 ) dx (12) = 0 dy 2x - 21 x = 0 dy -2y dx =-2x dy dx (-2y) = -2x dy -2x dx -2y dy x dx\f4.x = sec- x = 2 sec- 1 = tan ( sec () . 1 = tan () sec () . tan () sec (#) ax 1 = - - V2 1) dy = -yz tan () sec () ax ax tan () sec ()] =-yz V2 dx tan () sec (#) dy = -y2cos () cot ()5. sinx + 2cosy = 1 (sinx + 2cosby) = - (1) - (sinx ) + 2 - ( c dx (cosZy) = 0 cos x + 2 . - sin 2y - (2y) = 0 dy cos x - 2 sin Zy . 2 dy - = 0 dy cos x - 4 sin Zy dx y =0 dy dy (-4 sin 2y) = - cos x dy - COS x dx -4 sin 2y dy cos x dx 4 sin 2y