From the given recurrence, it follows that

and so on down to the first term,

(Notice how the exponent on the 2 and the subscript of <em>a</em> in the first term add up to <em>n</em> + 1.)
Denote the remaining sum by <em>S</em> ; then

Multiply both sides by 2 :

Subtract 2<em>S</em> from <em>S</em> to get

So, we end up with

My father taught me a method that I call, 'throwing some thing over the wall'. There is a sample equation for the first picture that shows you how it works. It's a great way to help isolate the variable and I hope that it works for you. The second picture contains the answers I got through the use of this method. I'm sorry for the messy handwriting; I was on a bus.
Answer:
x = 25
Step-by-step explanation:
x : (x+10) = 5:7
Fractional form
x / x+10 = 5/7
Cross multiply:
x * 7 = (x+10) * 5
7x = 5x + 50
7x - 5x = 5x + 50 - 5x
2x = 50
x = 25
Check:
25 : 25 + 10
25 : 35
25/35 = 5/7
If my answer is incorrect, pls correct me!
If you like my answer and explanation, mark me as brainliest!
-Chetan K
Im actually pretty sure its C because 4 to the power of 2 is 16 and then add those too up 16+25=41
Step-by-step explanation:
cos A = 16/20 = 4/5
tan A = 12/16 = 3/4
sin A = 12/20 = 3/5