# algebra

Evaluate giving exact values and identities. Calculator based solutions are not acceptable. Thanks for any help

cos (4pi/3 – 3pi/4)

1. 👍
2. 👎
3. 👁
1. Use the cos(A-B) identity.

1. 👍
2. 👎
👤
bobpursley
2. 4pi/3 – 3pi/4
= 7pi/12

1. 👍
2. 👎

## Similar Questions

1. ### Trigonometry help

If sin(x) = 1/3 and sec(y) = 13/12 , where x and y lie between 0 and π/2, evaluate the expression using trigonometric identities. (Enter an exact answer.) sin(x + y)

2. ### Math

If sin(x) = 1/3 and sec(y) = 29/21 , where x and y lie between 0 and π/2, evaluate the expression using trigonometric identities. (Enter an exact answer.) cos(2y)

A box without a lid is constructed from a 38 inch by 38 inch piece of cardboard by cutting in. squares from each corner and folding up the sides. a) Determine the volume of the box as a function of the variable . b) Use a graphing

4. ### Math

If sin(θ)=−4/7, and θ is in quadrant III, evaluate the following. Leave results as exact values (a)cos(θ)= (b) tan(θ)= (c) sec(θ)= (d) csc(θ)= (e) cot(θ)=

1. ### Chemistry

You have to prepare a pH 3.50 buffer, and you have the following 0.10M solutions available HCOOH, CH3COOH, H3PO4,CHOONa, CH3COONa, and NaH2PO4. a) What solutions would you use? b) How many milliliters of each solution would you

2. ### Calculus

The position of a particle in rectilinear motion is given by s(t) = tln(1/t) for t>0, where t is in seconds. A. Find the time (t>0) at which the velocity of the particle is 0. (I got t=1/e sec.) B. Find the particle's acceleration

3. ### chemistry DRBOB

Calculate the hydrogen ion concentration, in moles per liter, for solutions with each of the following pH values. pH=1.10 im guessing that this is what i did in my previous question except now i have to do it backwards. but i

4. ### Pre-Calculus

This question has me stuck. Use the Pythagorean identity sin^2 Θ + cos^2 Θ = 1 to derive the other Pythagorean identities, 1 + tan^2 Θ = sec^2 Θ and 1 + cot^2 Θ = csc^2 Θ. Discuss how to remember these identities and other

1. ### Calculus

Use your graphing calculator to evaluate to three decimal places the value of ∫ 0.5 to 3 ((sinx)/x)dx. I don’t have a graphing calculator so can I please have some help with this question? Thank you in advance!

2. ### Trigonometry

Find all solutions between 0 and 2pi. Round to two decimal places. In radians. Find all solutions between 0 and 2 pi. Round to two decimal places for the final solutions. The answers should be in radian mode. If you can use exact

3. ### Pure Mathematics

4) The roots of the equation z^2+2z+4=0 are denoted by α and β. a) find α and β in the form re^iθ, giving the values of r and θ b) Using de Moivre's Theorem, show that α^3=β^3. c) find the exact value of αβ*+α*β

4. ### Calc

Calculate the exact values of sin(theta) cos(theta) and tan (theta) when theta=240 degrees. How would I do this with and without a calculator?