Posted by **Jen** on Sunday, April 8, 2007 at 11:38am.

How to solve without calculator

1. sin(arctan(12/5))

2. cos(arccosx + arcsinx)

Thanks.

You have to know your right triangles.

5 12 13 is one. If the tan is 12/5, then the sin is 5/13. Draw a pic to confirm that.

On the second: Think. Draw any right triangle. Label the angles. Label the hypotenuse as 1, and the one sides as x. The other side will be sqrt (1-x^2). Notice the angle whose sine is x is teh complement of the angle whose cosine is x. Does that mean those two angles add to ninety degrees?

can't we do it by taking u=arctan(12/5)

no. arctan(12/5) is not equal to what you started out with.

- Inverse trigonometric function -
**Anonymous**, Saturday, October 24, 2015 at 6:21am
1.17

## Answer This Question

## Related Questions

- Trigonometry - I need help with I just can't seem to get anywhere. this is as ...
- MathsSs triG - Consider sin(x-360)sin(90-x)tan(-x)/cos(90+x) 1.A.SIMPLIFY sin(x-...
- Mathematics - Trigonometric Identities - Let y represent theta Prove: 1 + 1/tan^...
- math - Eliminate the parameter (What does that mean?) and write a rectangular ...
- Trig - Given: cos u = 3/5; 0 < u < pi/2 cos v = 5/13; 3pi/2 < v < ...
- math trigg. - which triangles do you use COS SIN or TAN?? You can use these ...
- Calculus - Okay so I have a question on my assignment that says: You are given ...
- calculus trigonometric substitution - ∫ dx/ (x^2+9)^2 dx set x = 3tan u dx...
- math - Can anyone help w/ these. 1) Solve the equation in the internal [0deg, ...
- Inverse trigonometric functions - How to find the value of arctan(2 sin (pi/3)) ...

More Related Questions