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:
20, 60, 15
Step-by-step explanation:
Let the third number be n, then
The first number is n + 5 and the second number is 4n
Sum the 3 numbers and equate to 95, that is
n + 5 + 4n + n = 95 ← collect like terms on left side
6n + 5 = 95 ( subtract 5 from both sides )
6n = 90 ( divide both sides by 6 )
n = 15
Thus
The first number is 15 + 5 = 20
The second number is 4 × 15 = 60
The third number is 15
Answer:
4.6
Step-by-step explanation:
Area of a circle: πr²
Data:
diameter: 21 cm
radius=diameter/2=21 cm/2=10.5 cm
area of this circle: π(10.5 cm)²=110.25π cm² (≈346.36 cm²)
Answer: area=110.25π cm²
