4)Given that sin 55degrees = 0.819 and cos20degrees = 0.94,

show how you would use the identities for sin(A+B) and cos(A+B) to find the following:

a) tan 35 degrees

Showing the steps you would follow. NOTE: sin^2theta+cos^2theta=1

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- Jun 17th 2010, 07:21 PMGAVREED2Trigonometric identity - HELP please
4)Given that sin 55degrees = 0.819 and cos20degrees = 0.94,

show how you would use the identities for sin(A+B) and cos(A+B) to find the following:

a) tan 35 degrees

Showing the steps you would follow. NOTE: sin^2theta+cos^2theta=1 - Jun 17th 2010, 08:50 PMProve It
- Jun 17th 2010, 09:12 PMundefined
I'm not entirely sure why they want you to use the angle sum identities, since there is a shorter way. The denominator cos(35) equals sin(90-35) = sin(55), which is given.

Likewise, the numerator sin(35) = cos(90-35) = cos(55), which is known after using the Pythagorean identity.