| 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 |  | quart.m0 |  |-  ( ph -> M =/= 0 ) | 
						
							| 18 |  | quart.i |  |-  ( ph -> I = ( sqrt ` ( ( -u ( S ^ 2 ) - ( P / 2 ) ) + ( ( Q / 4 ) / S ) ) ) ) | 
						
							| 19 |  | quart.j |  |-  ( ph -> J = ( sqrt ` ( ( -u ( S ^ 2 ) - ( P / 2 ) ) - ( ( Q / 4 ) / S ) ) ) ) | 
						
							| 20 | 1 2 3 4 1 6 7 8 9 10 11 12 13 14 15 16 | quartlem3 |  |-  ( ph -> ( S e. CC /\ M e. CC /\ T e. CC ) ) | 
						
							| 21 | 20 | simp2d |  |-  ( ph -> M e. CC ) | 
						
							| 22 | 21 | sqrtcld |  |-  ( ph -> ( sqrt ` M ) e. CC ) | 
						
							| 23 |  | 2cnd |  |-  ( ph -> 2 e. CC ) | 
						
							| 24 | 21 | sqsqrtd |  |-  ( ph -> ( ( sqrt ` M ) ^ 2 ) = M ) | 
						
							| 25 | 24 17 | eqnetrd |  |-  ( ph -> ( ( sqrt ` M ) ^ 2 ) =/= 0 ) | 
						
							| 26 |  | sqne0 |  |-  ( ( sqrt ` M ) e. CC -> ( ( ( sqrt ` M ) ^ 2 ) =/= 0 <-> ( sqrt ` M ) =/= 0 ) ) | 
						
							| 27 | 22 26 | syl |  |-  ( ph -> ( ( ( sqrt ` M ) ^ 2 ) =/= 0 <-> ( sqrt ` M ) =/= 0 ) ) | 
						
							| 28 | 25 27 | mpbid |  |-  ( ph -> ( sqrt ` M ) =/= 0 ) | 
						
							| 29 |  | 2ne0 |  |-  2 =/= 0 | 
						
							| 30 | 29 | a1i |  |-  ( ph -> 2 =/= 0 ) | 
						
							| 31 | 22 23 28 30 | divne0d |  |-  ( ph -> ( ( sqrt ` M ) / 2 ) =/= 0 ) | 
						
							| 32 | 13 31 | eqnetrd |  |-  ( ph -> S =/= 0 ) | 
						
							| 33 | 20 | simp1d |  |-  ( ph -> S e. CC ) | 
						
							| 34 | 33 | sqcld |  |-  ( ph -> ( S ^ 2 ) e. CC ) | 
						
							| 35 | 34 | negcld |  |-  ( ph -> -u ( S ^ 2 ) e. CC ) | 
						
							| 36 | 1 2 3 4 7 8 9 | quart1cl |  |-  ( ph -> ( P e. CC /\ Q e. CC /\ R e. CC ) ) | 
						
							| 37 | 36 | simp1d |  |-  ( ph -> P e. CC ) | 
						
							| 38 | 37 | halfcld |  |-  ( ph -> ( P / 2 ) e. CC ) | 
						
							| 39 | 35 38 | subcld |  |-  ( ph -> ( -u ( S ^ 2 ) - ( P / 2 ) ) e. CC ) | 
						
							| 40 | 36 | simp2d |  |-  ( ph -> Q e. CC ) | 
						
							| 41 |  | 4cn |  |-  4 e. CC | 
						
							| 42 | 41 | a1i |  |-  ( ph -> 4 e. CC ) | 
						
							| 43 |  | 4ne0 |  |-  4 =/= 0 | 
						
							| 44 | 43 | a1i |  |-  ( ph -> 4 =/= 0 ) | 
						
							| 45 | 40 42 44 | divcld |  |-  ( ph -> ( Q / 4 ) e. CC ) | 
						
							| 46 | 45 33 32 | divcld |  |-  ( ph -> ( ( Q / 4 ) / S ) e. CC ) | 
						
							| 47 | 39 46 | addcld |  |-  ( ph -> ( ( -u ( S ^ 2 ) - ( P / 2 ) ) + ( ( Q / 4 ) / S ) ) e. CC ) | 
						
							| 48 | 47 | sqrtcld |  |-  ( ph -> ( sqrt ` ( ( -u ( S ^ 2 ) - ( P / 2 ) ) + ( ( Q / 4 ) / S ) ) ) e. CC ) | 
						
							| 49 | 18 48 | eqeltrd |  |-  ( ph -> I e. CC ) | 
						
							| 50 | 39 46 | subcld |  |-  ( ph -> ( ( -u ( S ^ 2 ) - ( P / 2 ) ) - ( ( Q / 4 ) / S ) ) e. CC ) | 
						
							| 51 | 50 | sqrtcld |  |-  ( ph -> ( sqrt ` ( ( -u ( S ^ 2 ) - ( P / 2 ) ) - ( ( Q / 4 ) / S ) ) ) e. CC ) | 
						
							| 52 | 19 51 | eqeltrd |  |-  ( ph -> J e. CC ) | 
						
							| 53 | 32 49 52 | 3jca |  |-  ( ph -> ( S =/= 0 /\ I e. CC /\ J e. CC ) ) |