She used the diameter instead of the radius :) instead of cubing 8 she should’ve cubed 4
Answer:
Step-by-step explanation:
the directrix is y=-1
I don't know what the vertex focus is.
Answer:
The answer is tan²Ф + 1 = sec²Ф
Step-by-step explanation:
∵ sin²Ф + cos²Ф = 1 ⇒ ÷ cos²Ф both sides
∴ sin²Ф/cos²Ф + cos²Ф/cos²Ф = 1/cos²Ф
∵ sin²Ф/cos²Ф = tan²Ф
∵ 1/cos²Ф = sec²Ф
∴ tan²Ф + 1 = sec²Ф
Pretty sure it’s d(all of the above)