1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
AnnyKZ [126]
3 years ago
9

Which sum or difference identity would you use to verify that cos (180° - ∅) = -cos ∅?

Mathematics
2 answers:
Tom [10]3 years ago
6 0

Answer: Option C is correct


Step-by-step explanation:

We know tha tCos(A-B) = cosA cosB + sinAsinB

Plugging A = 180 and B = Ф

cos(180-Ф)= cos180cosФ+sin180sinФ

                  = (-1) cosФ+ (0) sinФ   [ since cos180=-1 and sin180 =0]

                 = -cosФ + 0

                 = -cosФ

Therefore option C is the correct answer.        

lara31 [8.8K]3 years ago
4 0

Answer:

Option (b) is correct.

b) \cos (\alpha-\beta)=\cos\alpha\cdot\cos\beta+\sin\alpha\cdot\sin\beta

Step-by-step explanation:

Given \cos (180^{\circ}-\phi)=-\cos \phi

To prove the above stated formula we have to choose one of the identity from the given options .

Since right side of above formula is 180^{\circ}-\phi which is same as \cos (\alpha-\beta), we will use the identity \cos (\alpha-\beta)

\cos (\alpha-\beta)=\cos\alpha\cdot\cos\beta+\sin\alpha\cdot\sin\beta

\cos (180^{\circ}-\phi)=\cos 180^{\circ}\cdot\cos\phi+\sin 180^{\circ}\cdot\sin\phi

We know  \cos 180^{\circ}=-1 and \sin 180^{\circ}=0

Substitute above, we get,

\cos (180^{\circ}-\phi)=-\cos \phi

Thus, Option (b) is correct.

You might be interested in
In dealing with surface area, what is a net?
Tju [1.3M]

Answer:

the answer is a.

when dealing with surface area, a net is a two-dimensional figure that can be cut out and folded up to make a three-dimensional solid

5 0
3 years ago
Read 2 more answers
Please answer correctly! I will mark Brainliest!
Pie

Answer:

its 60 all around

Step-by-step explanation:

5 0
3 years ago
Johannes want to earn at least $350 per week. His work week is 40 hrs, what is the minimum hourly wage he must make?
pentagon [3]

Answer: minimum hourly wage is $8.75

Step-by-step explanation:

To get the minimum hourly wage, we divide $350 by 40hrs

= $350 ÷ 40

= $8.75

3 0
3 years ago
Read 2 more answers
18.96 x 2.03 correct to 2 significant figures equals what?
Andreas93 [3]

9514 1404 393

Answer:

  38

Step-by-step explanation:

The product of the given numbers is 38.4888. Rounding this to two significant digits gets you 38.

6 0
3 years ago
Which expression is equal to the expression below?
Debora [2.8K]

Answer:

48

Step-by-step explanation:

(2*6)4

(12)4

48

Hoped it helped :)

4 0
3 years ago
Other questions:
  • Find the value of a?<br> A) 3 <br> B) 4 <br> C) 6 <br> D) 9
    8·2 answers
  • When x = 1, then what does y equal?
    6·1 answer
  • Identify the conic section represented by the equation y^2 -3x +4y +7 = 0
    15·2 answers
  • Did I do it right? Please help ASAP!
    8·1 answer
  • Bills car gets 30 miles to the go on. For every galon of gas it consumes his car runs 30 miles use this information to determine
    8·1 answer
  • The Staten Island Skating Pavilion charges a $5 entrance fee and an hourly rate for for ice skating. The total cost for ice skat
    9·1 answer
  • Please help fast this is the unit test
    11·1 answer
  • The high school band sold 500 tickets for a concert. The price of an adult ticket was $14.50, and the price of a student ticket
    14·1 answer
  • F(x) = 2x + 5<br> g(x) = x-5 divided by 2<br> What is f(g(x))?
    10·1 answer
  • Activity
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!