Answer:
The third one is the only one that is not a function.
Step-by-step explanation:
Step-by-step explanation:
solution:- from LHS 1-cos²x/sinx
∵ 1-cos²x = sin²x
∴ sin²x /sinx = sinx
from RHS tanx × cosx
∵tanx = sinx×cosx
∴ sinx/ cosx × cosx = sinx
Since, LHS = RHS proved ___
The series 7 + 16 + 25 +34 +43 +52 + 61 is an illusration of arithmetic series
The sigma notation of the series is: 
<h3>How to write the series in sigma notation?</h3>
The series is given as:
7 + 16 + 25 +34 +43 +52 + 61
The above series is an arithmetic series, with the following parameters
- First term, a = 7
- Common difference, d = 9
- Number of terms, n = 7
Start by calculating the nth term using:
a(n) = a + (n - 1) * d
This gives
a(n) = 7 + (n - 1) * 9
Evaluate the product
a(n) = 7 - 9 + 9n
Evaluate the difference
a(n) = 9n - 2
So, the sigma notation is:

Read more about arithmetic series at:
brainly.com/question/6561461
1/2, 3/6, 4/8, 5/10, etc.