1 + tan ² Ф=sec²Ф
1+(12/5)²=sec²Ф
169/25=sec² Ф
sec Ф=⁺₋√(169/25)=⁺₋13/5
sec Ф=1/cos Ф ⇒cosФ=1/sec Ф
cos Ф>0 ⇔ sec Ф>0 ⇔ sec Ф=+ 13/5
cos Ф=1/secФ
cos Ф=1 / 13/5=5/13
we can calculate the sin Ф, with this method.
sin²Ф + cos²Ф=1 ⇒ sin Ф=⁺₋√(1-cos² Ф)
sin Ф=⁺₋√[1-(5/13)²]=⁺₋12/13
like cos Ф>0 and tan Ф>0 ⇒ sin Ф>0 ⇒sin Ф=12/13
answer: d.12/13
other method
tan Ф=sin Ф / cos Ф
12/5=sin Ф / 5/13
sin Ф=(12/5)*(5/13)=12/13
answer: d.12/13
Answer: -1
Step-by-step explanation:
Un grouping in 3rd grade maths can also be called subtracting
Answer:
Step-by-step explanation:
perimeter of a rectangle = twice the length plus twice the width
P = 2L + 2W equation 1 P = 86 ft
Given the length is seven feet more than the width
L = W + 7 equation 2
Substitute equation 2 into equation 1
P = 2(W+7) + 2W = 86 ft
2W +14 + 2W = 86 ft
4W = 86 - 14
W = 72 / 4
W = 18 feet
"Over" usually means divide. First hint, check.
If we write it out, it looks like this:
This is the same as <em>some number divided by 7.</em>
