Question

Cos (90° - a) + sin(180° - a);

Answer 1

$\cos(90 {}^{ \circ} - \alpha ) + \sin(180 {}^{ \circ} - \alpha ) = \sin \alpha + \sin \alpha = 2 \sin \alpha .$

Использовали формулы приведения.

Answer 2

To simplify the expression cos(90° - a) + sin(180° - a), we can use trigonometric identities.

1. cos(90° - a): The angle 90° - a is the complement of angle a, so we can use the identity: cos(90° - a) = sin(a)

2. sin(180° - a): The angle 180° - a is the supplementary angle of angle a, so we can use the identity: sin(180° - a) = sin(a)

Now, we can simplify the expression:

cos(90° - a) + sin(180° - a) = sin(a) + sin(a)

Since both terms on the right-hand side are the same, we can combine them:

sin(a) + sin(a) = 2sin(a)

So, the simplified expression is 2sin(a).