Which of the following expressions is equivalent to sin ⁡ 7 8 ∘ cos ⁡ 3 4 ∘ − cos ⁡ 7 8 ∘ sin ⁡ 3 4 ∘ \sin78^{\circ}\cos34^{\circ}-\cos78^{\circ}\sin34^{\circ} sin 7 8 ∘ cos 3 4 ∘ − cos 7 8 ∘ sin 3 4 ∘ ?

sin ⁡ 4 4 ∘ \sin44^{\circ} sin 4 4 ∘

sin ⁡ 11 2 ∘ \sin112^{\circ} sin 11 2 ∘

cos ⁡ 4 4 ∘ \cos44^{\circ} cos 4 4 ∘

tan ⁡ 11 2 ∘ \tan112^{\circ} tan 11 2 ∘

Sum and Difference Identities

6. Trigonometric Identities and More Equations / Sum and Difference Identities / Problem 7

Problem 7

Which of the following expressions is equivalent to $\sin78^{\circ}\cos34^{\circ}-\cos78^{\circ}\sin34^{\circ}$ ?

$\sin44^{\circ}$

$\sin112^{\circ}$

$\cos44^{\circ}$

$\tan112^{\circ}$