Question

In a triangle abc right angle at c .If tan A 1/√3 find the value of cos A . cos B - sin A . sin B

Answer 1

Step-by-step explanation:

ABC is a right angled triangle in which

Angle C = 90°

tanA = 1/√3 = tan30°

A = 30°

angle B = 180° - ( 90°+30°)

angle B = 180° - 120° = 60°

Now ,

CosA*CosB - SinA*SinB

Cos(A+B)

Cos(30°+60°)

Cos90° = 0

Answer 2

Step-by-step explanation:

your answer is 0 .i tjink u got the ans by my explanation