In a right triangle, the sides are in the ratio 1: 1 :√2 , Angle of triangle are A,B and C. C is the right angle. Find cos A cos B – sin A sin B.
Given:
Ration of the sides of triangle 1: 1 :√2 ,
C is right angle.
Formula Used:
cos A cos B – sin A sin B = cos (A+ B)
Concept Used:
If two sides of a triangle is equal then their angles are also equal.
Solution:
cos A cos B – sin A sin B = cos (A+ B)
If two sides are equal then two angles will be equal . so, A = B, and sum of A + B = 90°
A + A = 90°
A = 45°
Cos 90° = 0
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