Question

sin25° = a and cos40°=b
Express the following in terms of a and b
(1-tan155° sin295° ) / (tan410° cos 230° )

Answer 1

You've got it. Great.

Answer 2

yoo

Answer 3

I just click wrongly
:(

Answer 4

\(\tan 155 = \tan(180-25) =\cdots \)

Answer 5

Yes, for each of the trig terms, you want to figure out how to write them as differences like this from standard trig functions. For example, with the one above:
because tan(180) = 0 and tan(-x) = -tan(x), it follows that

tan(180-25) = [ tan(180) - tan(25) ] / [ 1 - tan(180).tan(-25) ]
= - tan(25)
= - sin(25)/sqrt(1-sin^2(25))
= - a/sqrt(1-a^2)