Click to Chat

1800-2000-838

+91-120-4616500

CART 0

• 0

MY CART (5)

Use Coupon: CART20 and get 20% off on all online Study Material

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price: Rs.

There are no items in this cart.
Continue Shopping
Navjyot Kalra Grade: 10
`        sinx/cos3x + sin3x/Cos9x +sin9x/cos27x +sin27x/cos81x = 0. Find x.`
7 years ago

## Answers : (2)

147 Points
```										Dear
sinx/cos3x + sin3x/Cos9x +sin9x/cos27x  +sin27x/cos81x = 0
or sinxcosx/cos3xcosx   + sin3xcos3x/Cos9xcos3x +sin9xcos9x/cos27xcos9x  +sin27xcos27x/cos81xcos27x = 0
or  sin2x/cos3xcosx    + sin6x/Cos9xcos3x +sin18x/cos27xcos9x  +sin54x/cos81xcos27x = 0
or  sin(3x-x)/cos3xcosx    + sin(9x-3x)/Cos9xcos3x +sin(27x-9x)/cos27xcos9x  +sin(81x-27x)/cos81xcos27x = 0
0r tan3x -tanx +  tan9x-tan3x + tan27x -tan9x + tan81x -tan27x =0
tan81x - tanx  =0
tan81x = tanx
81x = kπ + x
x =  kπ/80     where k is any intiger
Please feel  free to post as many doubts on our discussion forum as you can. If you find any question Difficult to understand - post it here and we  will get you  the answer and detailed  solution very  quickly.   We are all IITians and here to help you in your IIT JEE preparation.  All the best.   Regards, Askiitians Experts Badiuddin
```
7 years ago
shreyaa sridhar
18 Points
```										how did sin(3x-x)/cos3xcosx become  tan3x -tanx

```
5 years ago
Think You Can Provide A Better Answer ?
Answer & Earn Cool Goodies

## Other Related Questions on Trigonometry

View all Questions »
• Complete JEE Main/Advanced Course and Test Series
• OFFERED PRICE: Rs. 15,900
• View Details