Question

Find exact value of cosine Theta for an angle Theta with a sine theta equals 3/8 and with its terminal side in quadrant 1

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Answer 1

B

Explanation:

Choice A is incorrect. Nothing is minus in quad 1.

Cos(theta) = sqrt(1 - sin^2(theta) )

Cos(theta) = sqrt(1 - (3/8)^2 )

Cos(theta) = sqrt(1 - 9/64)

cos(theta) = sqrt(55)/sqrt(64)

Cos(theta) = sqrt(55) / 8

Looks like B

Note: you should do this one before any of the others. It uses all the same general principles as the others.