Answer:
f(1) = 7
f(2) = 18
f(3) = 31
f(4) = 46
f(5) = 63
f(6) = 82
f(7) = 103
f(8) = 126
f(9) = 151
f(10) = 178
Step-by-step explanation:
f(1) = (-1)^2+8(1)-2 = 7
Continue plugging in values...
Step-by-step explanation:
<h3>
Need to FinD :</h3>
- We have to find the value of (sinθ + cosθ)/(sinθ - cosθ), when 13 cosθ - 5 = 0.

Here, we're asked to find out the value of (sinθ + cosθ)/(sinθ - cosθ), when 13 cosθ - 5 = 0. In order to find the solution we're gonna use trigonometric ratios to find the value of sinθ and cosθ. Let us consider, a right angled triangle, say PQR.
Where,
- PQ = Opposite side
- QR = Adjacent side
- RP = Hypotenuse
- ∠Q = 90°
- ∠C = θ
As we know that, 13 cosθ - 5 = 0 which is stated in the question. So, it can also be written as cosθ = 5/13. As per the cosine ratio, we know that,

Since, we know that,
- cosθ = 5/13
- QR (Adjacent side) = 5
- RP (Hypotenuse) = 13
So, we will find the PQ (Opposite side) in order to estimate the value of sinθ. So, by using the Pythagoras Theorem, we will find the PQ.
Therefore,



∴ Hence, the value of PQ (Opposite side) is 12. Now, in order to determine it's value, we will use the sine ratio.

Where,
- Opposite side = 12
- Hypotenuse = 13
Therefore,

Now, we have the values of sinθ and cosθ, that are 12/13 and 5/13 respectively. Now, finally we will find out the value of the following.

- By substituting the values, we get,


∴ Hence, the required answer is 17/7.
Answer:
68
Step-by-step explanation:
Let:
Number of girls invited = x
Number of boys = x +20
3/4 of boy showed up
2/3 of girls showed up
Exactly 19 did not show up
Therefore, we could say:
Fraction of boys that didn't show up = 1 - 3/4 = 1/4
Fraction of girls that didn't show up = 1 - 2/3 = 1/3
That is,
[1/4 *(x + 20)] + [1/3*x] = 19
[(x + 20) / 4] + x /3 = 19
(3(x + 20) + 4x) / 12 = 19
3x + 60 + 4x = 228
7x = 228 - 60
7x = 168
x = 168 / 7
x = 24
Number of girls, x = 24
Number of boys, x + 20 = 24 + 20 = 44
Total friends invited = (24 + 44) = 68