Click to Chat

1800-1023-196

+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
`        Find the nth derivative of cos2x × cos3x ?Please help me !!!!!!! `
one year ago

## Answers : (1)

Arun
24426 Points
```							Dear student cos x cos 2x cos 3x = cos 2x [ cos 4x + cos 2x ] /2 =(1/2)[ cos 4x cos 2x + cos^2 2x] =(1/4) [cos 6x + cos 2x + ( 1 + cos 4x)] = (1/4) [ 1 + cos 2x + cos 4x + cos 6x ] Now we have D^n ( cos (ax + b) = a^n cos ( n pi/2 + ax + b). Thus, D^n( cos x cos 2x cos 3x ) = D^n [ (1/4) { 1 + cos 2x + cos 4x + cos 6x}] = (1/4) [ 2^n cos(n pi/2 + 2x) + 4^n cos ( n pi/2 + 4x) + 6^n cos( n pi/2 + 6x) ]
```
one year ago
Think You Can Provide A Better Answer ?
Answer & Earn Cool Goodies

## Other Related Questions on Trigonometry

View all Questions »

### Course Features

• 731 Video Lectures
• Revision Notes
• Previous Year Papers
• Mind Map
• Study Planner
• NCERT Solutions
• Discussion Forum
• Test paper with Video Solution

### Course Features

• 31 Video Lectures
• Revision Notes
• Test paper with Video Solution
• Mind Map
• Study Planner
• NCERT Solutions
• Discussion Forum
• Previous Year Exam Questions