Answer:
c.7,999,999
Step-by-step explanation:
The phone number is of the form ABC - XXXX
A can be any number from 2 - 9. This means number of possible values for A are 8.
The rest of the places B,C and X can be any digit from 0 - 9. This means there are 10 possible values for each of these.
Since, value to A can be assigned in 8 ways, and to the rest of the 6 positions in 10 ways, according to the fundamental rule of counting, the total number of possible phone numbers that can be formed will be equal to the product of all the individual ways:
Total possible phone numbers = 8 x 10 x 10 x 10 x 10 x 10 x 10
Since, 1 of the given number: 867-5309 is not used, the total possible phone numbers will be:
Total possible phone numbers =
Hence, option C: 7,999,999 give the correct answer.
Answer:
Step-by-step explanation:
The domain of a function is all possible values for x.
There are restrictions on x.
The square root of a number can be undefined if that number is less than 0.
The value of x is all real numbers greater than or equal to 0.
<u>Answer:</u>
The basic identity used is .
<u>Solution: </u>
In this problem some of the basic trigonometric identities are used to prove the given expression.
Let’s first take the LHS:
Step one:
The sum of squares of Sine and Cosine is 1 which is:
On substituting the above identity in the given expression, we get,
Step two:
The reciprocal of cosine is secant which is:
On substituting the above identity in equation (1), we get,
Thus, RHS is obtained.
Using the identity , the given expression is verified.
