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1 vote
If sin theta=21/29
,what is cos theta

2 Answers

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20/29 is the cosine of theta
User Frbl
by
7.8k points
1 vote
To find cosine, you can use one of the formulas in the Pythagorean Identity, which is Sin^2 + Cos^2 = 1. Using this information, we can plug in sin into this equation.

So, (21/29)^2 + cos^2 = 1

(21/29)^2 = 441/841.
Bring this over to the other side by subtracting it by both sides, so

cos^2 = 1 - 441/841.
To subtract, convert the one to have the same denominator and then subtract, so

cos^2 = 841/841 - 441/841 = cos^2 = 400/841 (square root this)

cos = 20/29 that is your final answer.
User Taylorstine
by
8.1k points

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