Answer:
a. True. Rational numbers are closed under the sum operation, therefore, the sum of two rational numbers is always a rational number.
b. True. irrational numbers are closed under the sum operation, therefore, the sum of two irrationals numbers is always a irrational number.
c. True. The square of a real number is always a number greater than zero, and the sum of two numbers greater than zero is greater than zero.
d. True. The real numbers are closed under the product operation, then if a and b are reals numbers, the product ab is also a real number.
Step-by-step explanation:
Answer:
b/-7=4
b=4*-7
b= - 28
Step-by-step explanation:
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30 Answer:
Step-by-step explanation:SEARCH IT UP
1.
(3/4)^2 = (3/4)* (3/4)
(3/4)*(3/4)= 9/16
Final answer: 9/16
2.
11+6.4= 17.4
Final answer: 17.4
3.
9.5-2.8= 6.7
Final answer: 6.7
Answer:
56.39 nm
Step-by-step explanation:
In order to have constructive interference total optical path difference should be an integral number of wavelengths (crest and crest should be interfered). Therefore the constructive interference condition for soap film can be written as,

where λ is the wavelength of light and n is the refractive index of soap film, t is the thickness of the film, and m=0,1,2 ...
Please note that here we include an additional 1/2λ phase shift due to reflection from air-soap interface, because refractive index of latter is higher.
In order to have its longest constructive reflection at the red end (700 nm)

Here we take m=0.
Similarly for the constructive reflection at the blue end (400 nm)

Hence the thickness difference should be
