# Trigonometric Series

## Homework Statement

Reduce the following series to the most simplified form:

1. 2 sin$$^{2}$$($$\theta$$/2)*(1+cos$$\theta$$)*(1+cos$$^{2}$$$$\theta$$)(1+cos$$^{4}$$$$\theta$$)............

2. tan ($$\theta$$/2)*(1+sec $$\theta$$)(1+2$$\theta$$)(1+sec 4$$\theta$$)...................................

## Homework Equations

For problem 1:
2 sin$$^{2}$$($$\theta$$/2)=1-cos$$\theta$$)

## The Attempt at a Solution

For problem 1:
the result I got:
y=2$$^{(n+1)}$$

Result=
1-cos$$^{y}$$$$\theta$$

is it correct?????
For problem 2:
If I try to expand
sec 2 $$\theta$$
I get huge denominators which are difficult to solve. Similarly with tan ($$\theta$$/2),I again get a denominator with no pattern following any rule.

Please help me for the second one. and tell me if I am correct in solving the first problem.
regards,
Ritwik

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## Answers and Replies

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So I have finally got that latex code right. I have been trying the second problem for hours. Please help me.
Thanks in advance.
Regards,
Ritwik

HallsofIvy
Science Advisor
Homework Helper

## Homework Statement

Reduce the following series to the most simplified form:

1. 2 sin$$^{2}$$($$\theta$$/2)*(1+cos$$\theta$$)*(1+cos$$^{2}$$$$\theta$$)(1+cos$$^{4}$$$$\theta$$)............

2. tan ($$\theta$$/2)*(1+sec $$\theta$$)(1+2$$\theta$$)(1+sec 4$$\theta$$)...................................
I presume you mean
tan ($$\theta$$/2)*(1+sec $$\theta$$)(1+sec(2$$\theta$$))(1+sec 4$$\theta$$)

## Homework Equations

For problem 1:
2 sin$$^{2}$$($$\theta$$/2)=1-cos$$\theta$$)

## The Attempt at a Solution

For problem 1:
the result I got:
y=2$$^{n+1}$$
Result=
1-cos$$^{y}$$$$\theta$$

is it correct?????
There is no "n" in the problem so I have no idea what "y= 2n+1" means!

For problem 2:
If I try to expand
sec 2 $$\theta$$
I get huge denominators which are difficult to solve. Similarly with tan ($$\theta$$/2),I again get a denominator with no pattern following any rule.

Please help me for the second one. and tell me if I am correct in solving the first problem.
regards,
Ritwik
Since you say "huge denominators" I presume you switched to sine and cosine. That shouldn't be necessary. Use the corresponding identities as in (1) for tangent and secant.

I presume you mean
tan ($$\theta$$/2)*(1+sec $$\theta$$)(1+sec(2$$\theta$$))(1+sec 4$$\theta$$)

There is no "n" in the problem so I have no idea what "y= 2n+1" means!
'n' stands for the number of terms
Since you say "huge denominators" I presume you switched to sine and cosine. That shouldn't be necessary. Use the corresponding identities as in (1) for tangent and secant.
Yes I switched to sine and cosine. But I wonder which idntitis to use. I have been working over thse problms for 6 hours now. Could u please help???
Thanks

'n' stands for the number of terms

Yes I switched to sine and cosine. But I wonder which idntitis to use. I have been working over thse problms for 6 hours now. Could u please help???
Thanks
can this ever help 1+tan^2=sec^2
this is the only identity i know between sec and tan. Please help me someone

I really have been spending a wretched time to solve that
tan (x/2)*(1+sec x)(1+sec 2x)(1+sec 4x)...................................
How can I apply any identity here??
tan (x/2)=2 tan (x/4) / 1- tan^2 (x/4)
Please help!!!!!!

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