Ur answer is B- 4/5 because when u subtract them u get 0.8 and then u have to turn it as a fraction then it will be 8/10 then u simplify it and u get 4/5.

Hope u get it right!

7 0

4 years ago

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Verify the identity cot(x-pi/2)=-tan x

vampirchik [111]

To verify the identity we need the following identities:

i) $\displaystyle{ \cot(x)= \frac{\cos x}{\sin x}$

ii) $\displaystyle{ \sin (x-y)=\ sinx\cdot\ cosy -\ siny\cdot\ cosx$

iii) $\displaystyle{ \cos (x-y)=\ cosx\cdot \ cosy +\ sinx\cdot\ siny$ .

Also, we have know that $\displaystyle{ \sin \frac{ \pi }{2}=1$ and $\displaystyle{ \cos \frac{ \pi }{2}=0.$

Thus, $\displaystyle{ \cot(x-\frac{\pi}{2})= \frac{\cos (x-\frac{\pi}{2})}{\sin (x-\frac{\pi}{2})}$

By (ii) and (iii) we have:

$\displaystyle{ \frac{\cos (x-\frac{\pi}{2})}{\sin (x-\frac{\pi}{2})}= \frac{\ cosx\cdot \ cos\frac{\pi}{2} +\ sinx\cdot\ sin\frac{\pi}{2}}{\ sinx\cdot\ cos\frac{\pi}{2} -\ sin\frac{\pi}{2}\cdot\ cosx} = \frac{\ sinx}{-\cos x}$

by simplifying $\displaystyle{ \sin \frac{ \pi }{2}=1$ and $\displaystyle{ \cos \frac{ \pi }{2}=0.$

Now, $\displaystyle{ \frac{\ sinx}{-\cos x}$ is clearly -tanx.

4 0

3 years ago

Find the value of 64 3/2

Alisiya [41]

Answer:

65 1/2 or 65.5

Step-by-step explanation:

3/2 = 1.5 or 1 1/2

5 0

3 years ago

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Tests show that the hydrogen ion concentration of a sample of apple juice is 0.0003 and that of ammonia is 3.1 x 10^-9. Find the

scoundrel [369]

PH can be calculated using the following equation
pH = -log [H₃O⁺]
for apple juice the hydronium /hydrogen ion concentration is 0.0003
pH = -log (0.0003)
pH = 3.5
correct answer is C

For ammonia
pH = -log (3.1 x 10⁻⁹)
pH = 8.5
answer should be 8.5

5 0

3 years ago

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