Question

cos(40degree)cos(5degree)-sin(40degree)sin(5degree)
condense the trig expression. evaluate if possible

Answer 1

Here's the Answer :

cos40°cos5° - sin40°sin5°

= cos ( 40°+5°)

=cos45°

= 1/√2

The formula used here is

Cos(A+B) = cosAcosB - sinAsinB

Answer 2

Answer:

1/root2 i.e.0.707

Step-by-step explanation:

cos40°cos5°-sin40°sin5°

=cos (40°+5°)

=cos45°

=1/root2        

= 1/1.414      [ value of root 2 = 1.414]

=0.707

The formulae used here is

Cos(A+B) = cosAcosB-sinAsinB