Exapnd cos(40°) using a double angle identity. You do NOT need to type in the degree...

Question

Question

Exapnd cos(40°) using a double angle identity. You do NOT need to type in the degree symbol. Be sure to PREVIEW your answer b

math trigonometry

Answer 1

Answer #1

Solution:

The values provided in the questions are cos(40^o).

let

= cos(40^o)

By using double angle identity

cos(40^o) = cos(2*20^o) ---------------------->1

we know that formula

cos(2x) = 1 - 2sin²(x) -------------------->2 { x =20^o }

substitute eqation 2 formula into equation 1

cos(40^o) = cos(2*20^o) = 1 - 2sin²(20)

= 1 - 2*0.3420*0.3420

= 1 - 0.2339

cos(40^o). = 0.76607

Answer 2

Similar Homework Help Questions

Expand 2 cos(24u) using a double angle identity in terms of sines.

Expand 2 cos(24u) using a double angle identity in terms of sines.
Using a double-angle or half-angle formula to simplify the given expression (a) If cos? (24°) –...

Using a double-angle or half-angle formula to simplify the given expression (a) If cos? (24°) – sinº(24°) = cos(Aº) then A= Preview degrees (b) If cos? (5x) – sinº(5x) = cos(Bº) then B = Preview
QUESTION 12 Use a double-angle or half-angle identity to find the exact value of: cos(0) =...

QUESTION 12 Use a double-angle or half-angle identity to find the exact value of: cos(0) = and 270° <=< 360°, find sin 5 OAV10 10 B. 10 C. None of these OD 10 3 17 OE 4 QUESTION 13 Use a double-angle or half-angle identity to find the exact value of: 3 sin(0)= and 0° <o<90° , find tan 5 - šar 10 OA. 3 B.V10 Octs OD. -V10 E V30 QUESTION 11 Use a double-angle or half-angle identity to...

please answer 1,2 &3! 1. 2. 3. Rewrite the following expression using a double-angle identity. 2 cos...

please answer 1,2 &3! 1. 2. 3. Rewrite the following expression using a double-angle identity. 2 cos 2150 - 1 2 cos 2150 -1 = (Type an exact answer in simplified form. Use integers or fractions for any numbers in the expression.) 15 Given that sin 0 = - and cos 0 <0, determine sin (20), cos (20) and tan (20). 17 sin (20) = (Type a simplified fraction.) Complete the following statement. tan= 1 - cos 20 so tan 210x...
Use a double-angle identity to find the exact value of the expression 2 cos 15º -...

Use a double-angle identity to find the exact value of the expression 2 cos 15º - 1 OB. - 3 OA. 2 13 OC. 13 OD 2 V3 1 OF. OE 2 w Click to select your answer. Previous
2) (12 pts.) a. Write the double-angle identity: COS(20) = 2cos20 - 1 b. Make the...

2) (12 pts.) a. Write the double-angle identity: COS(20) = 2cos20 - 1 b. Make the substitution 6 = Solve for cos to obtain the half-angle identity for cosine. d. Repeat steps ac, starting with cos(20) = 1 - 2 sin²0 , to obtain the half-angle identity for sine. C.

Use a double-angle identity to find the exact value of the expression. 2 cos 267.5° -...

Use a double-angle identity to find the exact value of the expression. 2 cos 267.5° - 1 - 2
For sin 2x + cos x = 0, use a double-angle or half-angle formula to simplify...

For sin 2x + cos x = 0, use a double-angle or half-angle formula to simplify the equation and then find all solutions of the equation in the interval [0, 27). The answer is 21 = Preview , T2 = Preview 13 = Preview and 24 = Preview with Il < 22 23 24.
2 se the double-angle identities to verify the identity 1+cos(2x 2 cos* x = 9. Solve...

2 se the double-angle identities to verify the identity 1+cos(2x 2 cos* x = 9. Solve exactly over the indicated interval. a) sin(2x)-cos.x, all real numbers b) 2 cos(29) =-1, 0 θ < 2π

TT 7T T Write cos cos sin 2 4. function of one number. as a trigonometric...

TT 7T T Write cos cos sin 2 4. function of one number. as a trigonometric 2 Keep a in your answer. Be sure to PREVIEW your answer before submitting!