Question

3cosA - 4sinA=5 find 4cosA + 3 sinA??

Answer 1

3cosA - 4sinA=5 ...............(1)
4cosA + 3 sinA=X
squaring and adding we get
9(cos^2+sin^2)+16(cos^2+sin^2)=25+X^2
25=25+X^2
X^2=0
X=0