Question

5sin(5pi/2+a)-22cos(4pi+a) при cos a =0,7​

Answer 1

Ответ:     - 11,9 .

Объяснение:

Якщо cos α =0,7​  , то 5sin(5π/2+α)-22cos(4π+α) = 5sin( 2π + π/2 +α ) -

- 22cos(2*2π+α) = 5sin( π/2 +α ) - 22cos α = 5cos α - 22cos α = - 17cos α =

= - 17 * 0,7 = - 11,9 .

Answer 2

Ответ:

-11.9

Объяснение:

$5sin(\dfrac{5\pi}{2} + a) - 22 cos(4\pi + a) = 5\cdot cos~a-22\cdot cos~a = -17 \cdot cos~a$

Cos α = 0.7

-17 cos α = - 17 · 0.7 = - 11.9

Answer 3

To simplify the expression $5\sin\left(\frac{5\pi}{2}+a\right)-22\cos(4\pi+a)$ given that $\cos a = 0.7$, we can use trigonometric identities and substitute the given value for $\cos a$.

1. Use the identity $\sin(\theta) = \cos\left(\frac{\pi}{2} - \theta\right)$:

   $$5\sin\left(\frac{5\pi}{2}+a\right) = 5\cos\left(\frac{\pi}{2}-\left(\frac{5\pi}{2}+a\right)\right)$$

2. Use the identity $\cos(\theta + \pi) = -\cos(\theta)$:

   $$-22\cos(4\pi+a) = -22\cos(a)$$

3. Substitute $\cos a = 0.7$:

   $$-22\cos(a) = -22 \times 0.7$$

Now we can substitute these simplified expressions back into the original expression:

$$5\cos\left(\frac{\pi}{2}-\left(\frac{5\pi}{2}+a\right)\right) - 22 \times 0.7$$

Now, evaluate this expression using the given value of $\cos a = 0.7$.