given that sin (90-5 t ta )=cos180 - t ta...find d value of t ta

Answer 1

What is "t ta" ??
Where does "d" enter the picture?

Answer 2

I will assume that by t ta you mean Ø

so sin(90 - 5Ø) = cos(180 - Ø)
but sin(90 - 5Ø) = cos Ø
just like sin(90 - 30) = cos30

so we have
cos(5Ø) = cos(180-Ø)
take arccos of both sides
5Ø = 180-Ø
6Ø = 180
Ø = 30

Answer 3

Ø is the math symbol called "theta"

It comes from the 8th letter in the Greek alphabet:
http://www.omniglot.com/images/writing/classical_attic.gif