Question

if x cosB - cosA = 0 and y sinB - cosA = 0, then the value of cos^2A will be

Answer 1

Answer:

Step-by-step explanation:

x cosB - cosA = 0

taking square of this equation

(x cosB)^2 - 2xcosBcosA +cos^2A= 0

y sinB - cosA = 0

taking square of this equation

(y sinB)^2 - 2ysinBcosA +cos^2A= 0

add both equations

(x cosB)^2 +(y sinB)^2 - 2xcosBcosA - 2ysinBcosA +cos^2A +cos^2A=0

(x cosB)^2 +(y sinB)^2 - 2cosA(xcosB+ysinB) +2cos^2A =0

2cos^2A =2cosA(xcosB+ysinB)-(x cosB)^2 -(y sinB)^2

cos^2A =(2cosA(xcosB+ysinB)-(x cosB)^2 -(y sinB)^2) /2

Answer 2

Answer:

Step-by-step explanation: