Posted by **jeff** on Friday, May 28, 2010 at 9:23am.

I meant to type this one:

If the sine of an acute angle is 0.8, what is the sine of twice that angle?

1.60 or .64?

Thanks

- Algebra 2 -
**drwls**, Friday, May 28, 2010 at 11:15am
Neither. Sine can never exceed 1.

If the sine is 0.8, the cosine is 0.6.

(Think of a 3,4,5 right triangle, or use cos^2 = 1 - sin^2)

The sine is 2x is 2 sinx cosx.

In this case, that is 2*(3/5)(4/5)= 24/25

## Answer this Question

## Related Questions

- Algebra 2 .. - 1. An artist is designing triangular mirrors. Determine the ...
- Algebra 2.... - 1. An artist is designing triangular mirrors. Determine the ...
- Algebra2--- - 1. An artist is designing triangular mirrors. Determine the number...
- math - Which statement is ALWAYS true? A) The sine of an angle is equal to the ...
- Trigonometry - Cos D= -3/4. if the sine of the angle is positive, find the sine ...
- Math - calculus help needed example: sin-1(-1/2) how do you figure this out? The...
- trig - The tangent of an acute angle equals 1/2. What is the sine of the angle...
- Math - While evaluating the sine of a particular angle, an absent minded student...
- Physics - When light of a certain wavelength is incident normally on a certain ...
- PreCalc (Sine) - I'm having trouble understanding a sine concept. For instance, ...

More Related Questions