Answer:
Step-by-step explanation:
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Answer:
Ф = 
Step-by-step explanation:
It is a bit difficult to input the work here, so I uploaded an image
- First we can use the trig identities to change sec²(Ф) to tan²(Ф) + 1
- Then we can combine like terms
- Then we can factor this as a polynomial function
- Then we can set each term equal to zero and solve for Ф
- The first term tan(Ф) - 2 = 0 has no solution because tan(Ф) ≠ -2 anywhere
- The second term tan(Ф) - 1 = 0 has two solutions of
and
so these are the solutions to the problem
It would be 3 with be on the side and then 2/10
Note that
108° = 90° + 18°
so
sin(108°) = sin(90° + 18°) = sin(90°) cos(18°) + cos(90°) sin(18°) = cos(18°)
Then
sin²(108°) + sin²(18°) = cos²(18°) + sin²(18°) = 1
by the Pythagorean identity.
Potatoes cost $1.20 / kg. If you buy 0.8 kg, how much are the potatoes? (Answer $0.96)