Welcome :: Homework Help and Answers :: Mathskey.com
Welcome to Mathskey.com Question & Answers Community. Ask any math/science homework question and receive answers from other members of the community.

13,400 questions

17,804 answers

1,438 comments

42,189 users

urgent help please.

0 votes

Use the angle difference identity to find the exact value of each;

3) cos 75 °.

4)105 °.

8) Solve cos 2 θ = cos θ + 2 for 0 < θ < 2p

asked Jan 27, 2015 in PRECALCULUS by anonymous

3 Answers

0 votes

(3)

Step 1:

The trigonometric value is image.

Rewrite value as image.

image

Since  .

Substitute the values of  image and image.

image

Solution :

image.

answered Jan 27, 2015 by yamin_math Mentor
0 votes

(4)

Step 1:

The trigonometric value is .

Rewrite value as .

Since  .

Substitute the values of  and .

image

image

Solution :

image.

answered Jan 28, 2015 by yamin_math Mentor
0 votes

(8)

Step 1:

The trigonometric expression is .

Use the trigonometric identity .

image

image

image

image

The range of  image is image.

So image.

image.

Step 2:

The general solution of is ,where is integer.

image.

if then image.

if then

image

image is out of the interval image.

The solution of the trigonometric expression is image in the interval image.

Solution :

The solution of the trigonometric expression is  image.

answered Jan 28, 2015 by yamin_math Mentor
edited Jan 28, 2015 by yamin_math

Related questions

asked Oct 3, 2014 in CALCULUS by anonymous
asked Oct 3, 2014 in CALCULUS by anonymous
asked Oct 3, 2014 in CALCULUS by anonymous
asked Oct 2, 2014 in CALCULUS by anonymous
asked Oct 2, 2014 in CALCULUS by anonymous
asked Oct 2, 2014 in CALCULUS by anonymous
asked Oct 1, 2014 in CALCULUS by anonymous
asked Oct 1, 2014 in CALCULUS by anonymous
asked Jul 1, 2016 in PRECALCULUS by anonymous
asked Jul 1, 2016 in PRECALCULUS by anonymous
asked Jul 1, 2016 in PRECALCULUS by anonymous
...