If a + b equal to pi by 4 then prove that 1 + cot a into 1 + cot B equal to 2 into cot a into cot b

(cotA − 1) (cotB − 1) = 2

Step-by-step explanation:

A+B= π/4 = 180°/4 = 45°

A+B=45°

∴ cot(A+B)=cot45°

∴ cotBcotA−1 / (cotB+cotA) = 1

⇒cotB + cotA = cotBcotA = 1

⇒cotB + cotA − cotBcotA + 1 = 0

⇒cotBcotA − cotB − cotA − 1 = 0

⇒cotBcotA − cotB − cotA − 1 + 2 = 0+2

⇒cotBcotA − cotB − cotA + 1 = 2

⇒cotB(cotA − 1) (cotA − 1) = 2

⇒(cotA − 1) (cotB − 1) = 2

Proved

answer: the answer is 23

step-by-step explanation:

the multiples of 15 are 15, 30,45, 60, 75, 90, 105, 120, 135, 150, 165, 180, 195,   210, 225, 240, 255, 270, 285, 300, 315, 330, 345, 360, 375,   390, 405, 420, 435, 450, 465, 480, 495, 510, 525, 540, 555, 570, 585, 600, 615, 630, 645, 660, 675, 690, 705, 720, and 735.

the factors of 15 are 1, 3, 5, and 15.

hope that , fam!

-une, your fren : )