Q13 of 268 Page 4

Show by an example that
sin A – sin B ≠ sin (A – B)

Let A = 60^o and B = 30^o, then

L.H.S. = sin A - sin B = sin 60^o - sin 30^o

R. H. S. = sin (A - B) = sin (60^o - 30^o) = sin 30^o

∴ L.H.S. R.H.S

Show by an example that

cos C + cos D ≠ cos (C + D)

Show by an example that

sin A + sin B ≠ sin (A + B)

In a right hypotenuse AC = 10 cm and ∠A = 60°, then find the length of the remaining sides.

In a rectangle ABCD, BD : BC = 2 : √3, then find ∠BDC in degrees.

Show by an example thatsin A – sin B ≠ sin (A – B)