Question

Sin(5x+15)=cos(4x−6)

Answer 1

Answer:

Step-by-step explanation:

you know ; for all reals a ; cos(π/2 - a) = sin(a)

so : sin(5x+15) = cos(π/2-(5x+15) ) = cos(π/2-5x-15)

sin(5x+15)=cos(4x−6)  eqivaut : cos(π/2-5x-15) = cos(4x−6)

note : cos(a)=cos(b)  :  a= b +2kπ  or a= - b +2kπ ....k in Z

π/2-5x-15 = 4x−6 + 2kπ    or π/2-5x-15 = - (4x−6) + 2kπ....k in Z

continue calculate : x .......