Question

if cos theta + s theta = 5/2 ,find the value of cos square theta + sec square theta​

Answer 1

Answer:

cos theta+sec theta=5/2

(cos theta+sec theta)²=(5/2)²[squaring on both sides]

cos²theta+sec²theta+2×costheta×sectheta=25/4

cos²theta+sec²theta+2×costheta×1/costheta=25/4

[sec theta=1/cos theta]

cos²theta+sec²theta+2=25/4

cos²theta+sec²theta=25/4 -2

cos²theta+sec²theta=25/4 -8/4

cos²theta+sec²theta=17/4