表达式2: "y" Subscript, 1 , Baseline left parenthesis, "t" , right parenthesis equals 3 "t" cubed plus 3y1t=3t3+3
2
表达式3: left parenthesis, "x" Subscript, 1 , Baseline left parenthesis, "t" , right parenthesis , "y" Subscript, 1 , Baseline left parenthesis, "t" , right parenthesis left brace, negative 5 less than or equal to "t" less than or equal to "a" , right brace , right parenthesisx1t,y1t−5≤t≤a
定义域t最小值： negative 5−5
less than or equal to "t" less than or equal to≤t≤
