Step-by-step explanation:
sin⁴ x − sin² x
Factor:
(sin² x) (sin² x − 1)
Pythagorean identity:
(1 − cos² x) (-cos² x)
Distribute:
-cos² x + cos⁴ x
cos⁴ x − cos² x
1L=1000mL
2800 mL=2.8L
If she needs 3.5 L, she currently has 2.8L,
so 3.5-2.8=0.7 L more or .7x1000=700 more mL
