Answer:
Step-by-step explanation:
2 cos(A+45)cos (B-45)
=2[cos A cos 45-sin A sin 45][cos B cos 45+sin B sin 45]
=2[cos A ×1/√2-sin A ×1/√2][cos B×1/√2+sin B×1/√2]
=2[1/√2(cos A-sin A)][1/√2(cos B-sin B]
=2×1/√2×1/√2 (cos A-sin A)(cos B+sin B)
=cosA cos B+cos A sin B-sin A cos B-sin A sin B
=cos A cos B-sin A sin B-(sin A cos B-cos A sin B)
=cos (A+B)-sin (A-B)
i think there should be A in place of B.
then
=cos (A+A)-sin (A-A)
=cos 2A-sin 0
=cos 2A
as sin 0=0
It is given that AB is parellel to CD. These two lines are cut by a transversal, creating angles BAC and DCA. Thus, angle BAC is congruent to angle DCA because alternate interior angles are congruent. It is also given that angle ACB is congruent to angle CAD. Therefore, triangle ABC is congruent to triangle CDA because of the ASA theorem.
All you have to do is add up the numbers
Answer:
1. Anne = 21 Bobby=35, 450, 70+40+30=140
Step-by-step explanation:
- 1 21÷3=7
- 7×5=35
- 7-2=250
- 5=250
- 1=50
- 2×50+7×50=100+350=450
- 450
- we can see that it's multiplied by 10, so 70+40+30=140
Using the combination formula, it is found that she can select the shirts in 775,200 ways.
The order in which the shirt are chosen is not important, hence, the <em>combination formula</em> is used to solve this question.
Combination formula:
is the number of different combinations of x objects from a set of n elements, given by:
In this problem:
- 3 shirts from a set of 17.
- Then, 3 shirts from a set of 20.
- They are independent, hence, to find the total, we multiply both combinations.
She can select the shirts in 775,200 ways.
To learn more about the combination formula, you can check brainly.com/question/25821700
