Thank you for registering.

One of our academic counsellors will contact you within 1 working day.

Please check your email for login details.
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

X=sin70°sin50° y=cos60°cos80°,then xy?please give detailed explanation soon......

X=sin70°sin50° y=cos60°cos80°,then xy?please give detailed explanation soon......

Question Image
Grade:12th pass

1 Answers

KESHAV
19 Points
3 years ago
Given  Sin 50 sin 70 . cos 60 cos 80
 
=cos(90-30) cos(90-10) . Sin 50 sin 70 
 
Sin 10 Sin 30 Sin 50 sin 70

⇒ (1/ 2) Sin 10 Sin 50 sin 70   multiply and divide with 2 Cos 10

⇒ 2 Cos 10 Sin 10 Sin 50 sin 70 / (2 x 2 Cos 10)  { 2SinA Cos A = Sin2A }

⇒  Sin 20  Sin 50 sin 70 / ( 4 Cos 10)    multiply and divide with 2 

⇒ 2 x Sin 20  Sin 50 sin (90 - 20) / (2 x 4 Cos 10

⇒ 2 Sin 20 Cos 20 Sin 50 / 8 Cos 10

⇒ Sin 40  Sin 50 / 8 Cos 10   { 2SinA Cos A = Sin2A }

Again multiply and divide with 2 .

⇒ 2 x Sin 40  Sin ( 90 - 40)  / 2 x 8 Cos 10.

⇒ 2 x Sin 40  Cos 40 / 2 x 8 Cos ( 90 - 80)

⇒ Sin 80  / 16 Sin 80 = 1 / 16.

Think You Can Provide A Better Answer ?

Provide a better Answer & Earn Cool Goodies See our forum point policy

ASK QUESTION

Get your questions answered by the expert for free