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I need help I don’t get it

I need help I don’t get it-example-1
User Jkaufmann
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1 Answer

4 votes

Answer:

  • sin(θ) = (√7)/4
  • tan(θ) = (-√7)/3

Explanation:

You want the sine and tangent of the 2nd-quadrant angle whose cosine is -3/4.

Identities

The relevant trig identities are ...

sin(θ) = ±√(1 -cos(θ)²) . . . . . the + sign applies in the 2nd quadrant

tan(θ) = sin(θ)/cos(θ)

Application

Using the given value of cosine, we find the sine to be ...

sin(θ) = √(1 -(-3/4)²) = √(7/16)

sin(θ) = (√7)/4

and

tan(θ) = sin(θ)/cos(θ) = ((√7)/4)/(-3/4)

tan(θ) = (-√7)/3

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I need help I don’t get it-example-1
User Nilanchala
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8.2k points

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