Use the diagram to complete the statements about how to prove the cosine sum identity. A unit circle. Point P is on the circle on the x-axis at (1, 0). Point S is in quadrant 4 on (cosine (negative beta), sine (negative beta) ). Point Q is in quadrant 1 above point P at (cosine (alpha), sine (alpha) ). Point R is above point Q at (cosine (alpha + beta), sine (alpha + beta) ). Triangles AOC and BOD are congruent by SAS. Therefore, and these lengths can be found using the . Because this is the unit circle, the coordinates of points A, B, and D are equal to cosine and sine of Alpha + Beta , Alpha, and –β, respectively. Write expressions for the lengths and set them equal. Rewrite cos(-Beta) and sin(-Beta) using the identities before squaring both sides of the equation. Simplifying the resulting expressions involving cosine and sine of Alpha, Beta, and Alpha + Beta requires using the identity. When simplified, the equation becomes cos(Alpha + Beta) = cos(Alpha)cos(Beta) - sin(Alpha)sin(Beta).

AC=BD

distance formula

Pythagorean identity

Step-by-step explanation:

just did it on edge

2 & 7

step-by-step explanation:

he climbs 300 ft/hr at a constant rate. the peak is at 1,500 ft.

when going up, he reaches 600 ft in 2 hours. remember, that he is going in a constant rate. divide 600 with 300:

600/300 = 2

assuming that he takes the same route back (meaning that it's a 1500 ft route back, you can solve.

note also that you are solving when he gets back to 600 ft after he reaches the peak.

first, find the amount of hours it takes to get up the peak. divide the total amount (1500), with the ft/her (300) to get the amount of hours (x):

1500/300 = x

x = 5

it takes jamie 5 hours to get up. now, he is returning down, and reaches 600 (his current destination). remember that he climbs at a constant 300 ft/hr. divide 600 with 300:

600/300 = x

x = 2

now add the two numbers together.

x = 5 + 2 = 7

jamie takes 7 hours to go up the mountain and reach his current position when descending.

(total amount/constant rate) = (time).

remember that it is a constant rate, so in total, when he gets back down the mountain, it will take the same amount of time as when he goes up. the total amount for the round trip is: 5 + 5 = 10.

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