Answer: the answer is 54
Step-by-step explanation: The error in the expression was that it was multiplied by 1 so it can't be one unless it was also 1 and it's not it is 54.
Answer:
D. Pythagorean
Step-by-step explanation:
Given the identity
cos²x - sin²x = 2 cos²x - 1.
To show that the identity is true, we need to show that the left hand side is equal to right hand side or vice versa.
Starting from the left hand side
cos²x - sin²x ... 1
According to Pythagoras theorem, we know that x²+y² = r² in a right angled triangle. Coverting this to polar form, we have:
x = rcostheta
y = rsintheta
Substituting into the Pythagoras firnuka we have
(rcostheta)²+(rsintheta)² = r²
r²cos²theta+r²sin²theta = r²
r²(cos²theta+sin²theta) = r²
(cos²theta+sin²theta) = 1
sin²theta = 1 - cos²theta
sin²x = 1-cos²x ... 2
Substituting equation 2 into 1 we have;
= cos²x-(1-cos²x)
= cos²x-1+cos²x
= 2cos²x-1 (RHS)
This shows that cos²x -sin²x = 2cos²x-1 with the aid of PYTHAGORAS THEOREM
15a-25=35
3.333
Leah needs to buy some apples from the grocery store. She places fifteen apples in her cart and proceeds to the checkout. Lucky for her, there happens to be a discount on apples for the day. She saves $25 on her purchase. The total money she ends up spending was only $35 (excluding tax). How much did each apple cost?
Answer:
Minimum number of calls = 10
Step-by-step explanation:
Lets name the five people as A,B,C,D and E.
<u>On the night before ,each person talks to every other person atleast once that means A would talk to B,C,D and E atleast once.</u>
Lets start with A. He would talk to other 4 people which means there would be 4 phone calls made.
Now lets take B. He can talk to A,C,D and E. But A has already talked to C therefore to get minimum number of phone calls , B need not call A again. So he calls only C,D and E.
In case of C using similar logic he need to talk to only D and E.
For D , he talks to E alone.
E does not have to talk to anyone as he has already talked to everyone atleast once.
Total calls = 4 + 3 + 2 + 1
= 10
