| Step | Hyp | Ref | Expression | 
						
							| 1 |  | quart.a |  |-  ( ph -> A e. CC ) | 
						
							| 2 |  | quart.b |  |-  ( ph -> B e. CC ) | 
						
							| 3 |  | quart.c |  |-  ( ph -> C e. CC ) | 
						
							| 4 |  | quart.d |  |-  ( ph -> D e. CC ) | 
						
							| 5 |  | quart.x |  |-  ( ph -> X e. CC ) | 
						
							| 6 |  | quart.e |  |-  ( ph -> E = -u ( A / 4 ) ) | 
						
							| 7 |  | quart.p |  |-  ( ph -> P = ( B - ( ( 3 / 8 ) x. ( A ^ 2 ) ) ) ) | 
						
							| 8 |  | quart.q |  |-  ( ph -> Q = ( ( C - ( ( A x. B ) / 2 ) ) + ( ( A ^ 3 ) / 8 ) ) ) | 
						
							| 9 |  | quart.r |  |-  ( ph -> R = ( ( D - ( ( C x. A ) / 4 ) ) + ( ( ( ( A ^ 2 ) x. B ) / ; 1 6 ) - ( ( 3 / ; ; 2 5 6 ) x. ( A ^ 4 ) ) ) ) ) | 
						
							| 10 |  | quart.u |  |-  ( ph -> U = ( ( P ^ 2 ) + ( ; 1 2 x. R ) ) ) | 
						
							| 11 |  | quart.v |  |-  ( ph -> V = ( ( -u ( 2 x. ( P ^ 3 ) ) - ( ; 2 7 x. ( Q ^ 2 ) ) ) + ( ; 7 2 x. ( P x. R ) ) ) ) | 
						
							| 12 |  | quart.w |  |-  ( ph -> W = ( sqrt ` ( ( V ^ 2 ) - ( 4 x. ( U ^ 3 ) ) ) ) ) | 
						
							| 13 |  | quart.s |  |-  ( ph -> S = ( ( sqrt ` M ) / 2 ) ) | 
						
							| 14 |  | quart.m |  |-  ( ph -> M = -u ( ( ( ( 2 x. P ) + T ) + ( U / T ) ) / 3 ) ) | 
						
							| 15 |  | quart.t |  |-  ( ph -> T = ( ( ( V + W ) / 2 ) ^c ( 1 / 3 ) ) ) | 
						
							| 16 |  | quart.t0 |  |-  ( ph -> T =/= 0 ) | 
						
							| 17 |  | 2cn |  |-  2 e. CC | 
						
							| 18 | 1 2 3 4 7 8 9 | quart1cl |  |-  ( ph -> ( P e. CC /\ Q e. CC /\ R e. CC ) ) | 
						
							| 19 | 18 | simp1d |  |-  ( ph -> P e. CC ) | 
						
							| 20 |  | mulcl |  |-  ( ( 2 e. CC /\ P e. CC ) -> ( 2 x. P ) e. CC ) | 
						
							| 21 | 17 19 20 | sylancr |  |-  ( ph -> ( 2 x. P ) e. CC ) | 
						
							| 22 | 1 2 3 4 1 6 7 8 9 10 11 12 | quartlem2 |  |-  ( ph -> ( U e. CC /\ V e. CC /\ W e. CC ) ) | 
						
							| 23 | 22 | simp2d |  |-  ( ph -> V e. CC ) | 
						
							| 24 | 22 | simp3d |  |-  ( ph -> W e. CC ) | 
						
							| 25 | 23 24 | addcld |  |-  ( ph -> ( V + W ) e. CC ) | 
						
							| 26 | 25 | halfcld |  |-  ( ph -> ( ( V + W ) / 2 ) e. CC ) | 
						
							| 27 |  | 3nn |  |-  3 e. NN | 
						
							| 28 |  | nnrecre |  |-  ( 3 e. NN -> ( 1 / 3 ) e. RR ) | 
						
							| 29 | 27 28 | ax-mp |  |-  ( 1 / 3 ) e. RR | 
						
							| 30 | 29 | recni |  |-  ( 1 / 3 ) e. CC | 
						
							| 31 |  | cxpcl |  |-  ( ( ( ( V + W ) / 2 ) e. CC /\ ( 1 / 3 ) e. CC ) -> ( ( ( V + W ) / 2 ) ^c ( 1 / 3 ) ) e. CC ) | 
						
							| 32 | 26 30 31 | sylancl |  |-  ( ph -> ( ( ( V + W ) / 2 ) ^c ( 1 / 3 ) ) e. CC ) | 
						
							| 33 | 15 32 | eqeltrd |  |-  ( ph -> T e. CC ) | 
						
							| 34 | 21 33 | addcld |  |-  ( ph -> ( ( 2 x. P ) + T ) e. CC ) | 
						
							| 35 | 22 | simp1d |  |-  ( ph -> U e. CC ) | 
						
							| 36 | 35 33 16 | divcld |  |-  ( ph -> ( U / T ) e. CC ) | 
						
							| 37 | 34 36 | addcld |  |-  ( ph -> ( ( ( 2 x. P ) + T ) + ( U / T ) ) e. CC ) | 
						
							| 38 |  | 3cn |  |-  3 e. CC | 
						
							| 39 | 38 | a1i |  |-  ( ph -> 3 e. CC ) | 
						
							| 40 |  | 3ne0 |  |-  3 =/= 0 | 
						
							| 41 | 40 | a1i |  |-  ( ph -> 3 =/= 0 ) | 
						
							| 42 | 37 39 41 | divcld |  |-  ( ph -> ( ( ( ( 2 x. P ) + T ) + ( U / T ) ) / 3 ) e. CC ) | 
						
							| 43 | 42 | negcld |  |-  ( ph -> -u ( ( ( ( 2 x. P ) + T ) + ( U / T ) ) / 3 ) e. CC ) | 
						
							| 44 | 14 43 | eqeltrd |  |-  ( ph -> M e. CC ) | 
						
							| 45 | 44 | sqrtcld |  |-  ( ph -> ( sqrt ` M ) e. CC ) | 
						
							| 46 | 45 | halfcld |  |-  ( ph -> ( ( sqrt ` M ) / 2 ) e. CC ) | 
						
							| 47 | 13 46 | eqeltrd |  |-  ( ph -> S e. CC ) | 
						
							| 48 | 47 44 33 | 3jca |  |-  ( ph -> ( S e. CC /\ M e. CC /\ T e. CC ) ) |