# pre calc

posted by .

use an appropriate half-angle formula to find the exact value ofthe expression.
tan22.5

write the product as a sum
sinxsin5x

write the sum as a product
sin2x-sin7x

• pre calc -

sinxsin5x
sinucosv= 1/2[cos(u-v)-cos(u+v)]

= 1/2[cos(x-5x)-cos(x+5x)]

= 1/2[cos(-4x)-cos(6x)]

= 1/2cos4x-1/2cos6x

## Similar Questions

1. ### math

Find the two numbers that multiply to the product number and add to the sum number of the following: a)Product 563033256; Sum 51895 b)Product -43481220; Sum 28429 c)Product 2545124358; Sum -105619 I tried xy = product and x+y = sum, …
2. ### Math (Calc)

Find the Exact value of Pi/24. I'm not sure whether to use a half-angle formula or a difference/sum of angles formula.
3. ### MATH

1.)Find the exact solution algebriacally, if possible: (PLEASE SHOW ALL STEPS) sin 2x - sin x = 0 2.) GIVEN: sin u = 3/5, 0 < u < ï/2 Find the exact values of: sin 2u, cos 2u and tan 2u using the double-angle formulas. 3.)Use …
4. ### pre calc

Use the sum-to-product formula to simplify the expression: If sin 52 + sin 8 = sin A, 0<A<90, then A =?
5. ### Math

1. use the suitable product-to-sum formula to rewrite the following expression: sin(13x/2)sin(5x/2) 2. Find value of cos(255degrees)cos(105degrees) is it 1/4?
6. ### Math

Use the product-to-sum formulas to write the product as a sum or difference. sin(x+y) * cos(x-y)
7. ### Algebra 2

Q: Write a quadratic equation with integral coefficients whose roots are -6+i and -6-i My Answer: x^2+12x+37 (first) sum=-12 product=37 (then) write equation using formula x^2-(sum)x+product Is my work and answer correct?
8. ### Pre Calculus

Use the sum-to-product formulas to find the exact value of the given expression. sin 150° + sin 30°
9. ### maths

Use the product-to-sum formula to write the given product as a sum or difference. 6sin π/10 cos π/ 10
10. ### Math

A. Write 60 as the sum of two numbers. B. Write 60 as the product of two numbers. C. Write 60 as the product of two factors. In youe expression, write one of the factors as a sum of two numbers. Find an equivalent way to write this …

More Similar Questions