,L[]CASE ,PHI ,EXAMPLES #A4 ,L[]CASE PHI EQUALS OP5 FRAC;N PI OV] TWO CLOSE FRAC;N IS WRITT5 _% .F .K ?.P/2# _: #B4 ,OP5 FRAC;N "O OV] ! SECANT ( PHI CLOSE FRAC;N EQUALS ! COS9E ( PHI IS WRITT5 _% ?1/SEC .F# .K COS .F _: #C4 ,! COS9E ( OP5 P>5!SIS PI M9US PHI CLOSE P>5!SIS EQUALS NEGATIVE COS9E ( PHI IS WRITT5 _% COS (.P-.F) .K -COS .F _: #D4 ,! COS9E ( TWO PHI EQUALS TWO COS9E SQU>$ PHI M9US "O IS WRITT5 _% COS #2.F .K #2COS^2 .F-1 _: #54 ,COS9E SQU>$ PHI EQUALS "O M9US S9E SQU>$ PHI IS WRITT5 _% COS^2 .F .K #1-SIN^2 .F _: #64 ,! SECANT ( OP5 P>5!SIS NEGATIVE PHI CLOSE P>5!SIS EQUALS ! SECANT ( PHI IS WRITT5 _% SEC (-.F) .K SEC .F _: #A