cos 68° cos 8° + sin 68° sin 8° = ?
  • a)
    1/2
  • b)
    1/4
  • c)
    1
  • d)
    0
Correct answer is option 'A'. Can you explain this answer?

Related Test

Answers

According to trigonometric functions cos A cos B + sin A sin B = cos (A-B) Therefore let A=68 and B=8 => cos (68-8) = cos 60 = 1/2 Hope you understand this.......

Shivani
Jun 11, 2018
CosAcosB+sinAsinB=cos(A-B).....here A=68...B=8....cos68cos8+sin68sin8=cos(68-8)=cos60=1/2....option A HOPE U GOT IT...

Yogesh Singla
Jun 21, 2018
Yes as it becomes the formula of cos(a-b). so cos(68-8)= cos(60) = 1/2

Pioneer Academy
Feb 18, 2022
We know, 
cosA cosB + sinA sinB = cos(A-B)
cos 68° cos 8° + sin 68° sin 8° = Cos (68-8) = Cos60°
=1/2

According to trigonometric functions cos A cos B + sin A sin B = cos (A-B) Therefore let A=68 and B=8 => cos (68-8) = cos 60 = 1/2 Hope you understand this.......
According to trigonometric functions cos A cos B + sin A sin B = cos (A-B) Therefore let A=68 and B=8 => cos (68-8) = cos 60 = 1/2 Hope you understand this.......