Trig using Sum and Difference Formulas

[bluewater]

here's the work i got so far. i guess what im trying to get help for this problem is the last few steps at the end
1. tan15 degrees
tan(A-B)=(tanA-tanB)/(1+tanAtanB)
tan(45-30)=(tan45-tan30)/(1+tan45tan30)
tan(45-30)=[1-(√3/3)]/[(1+1(√3/3)]
tan(45-30)=[1-(√3/3)]/[(1+1(√3/3)]*3
tan(45-30)=(3-√3)/(3+√3)


answer = 2 - √3



completely stuck on this problem.
2. sin (17pi/12)




Thanks in advance.

[Subhotosh Khan]

here's the work i got so far. i guess what im trying to get help for this problem is the last few steps at the end
1. tan15 degrees
tan(A-B)=(tanA-tanB)/(1+tanAtanB)
tan(45-30)=(tan45-tan30)/(1+tan45tan30)
tan(45-30)=[1-(√3/3)]/[(1+1(√3/3)]
tan(45-30)=[1-(√3/3)]/[(1+1(√3/3)]*3
tan(45-30)= (3-√3)/(3+√3) ................rationalize the denominator

tan 15° = [(3-√3)/(3+√3)] * [(3-√3)/(3-√3)] = (3-√3)²/[3² - (√3)²] = (9 - 6√3 + 3)/(9 - 3)

Now continue...

answer = 2 - √3



completely stuck on this problem.
2. sin (17pi/12) = sin(π + 5π/12) = - sin(5π/12) = - sin (π/4 + π/6) ... Now continue ...




Thanks in advance.

[Chadmama]

HI guys

Power-reduction formulas. 8 Product-to- sum and sum-to-product can be shown by using either the sum and difference identities or the multiple-angle formulae.and simplifying the right hand side of each formula using the Angle Sum and Difference Theorem will produce the left hand side


Thanks

[Denis]

Power-reduction formulas. 8 Product-to- sum and sum-to-product can be shown by using either the sum and difference identities or the multiple-angle formulae.and simplifying the right hand side of each formula using the Angle Sum and Difference Theorem will produce the left hand side
Thanks

What is your point, mama?